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Background Proanthocyanidins (PAs) have always been considered as important medicinal value component. In order to gain insights into the PA biosynthesis regulatory network in I. stachyodes roots, we analyzed the transcriptome of the I. stachyodes in Leaf, Stem, RootI (one-year-old root), and RootII (two-year-old root). Results In this study, a total of 110,779 non-redundant unigenes were obtained, of which 63,863 could be functionally annotated. Simultaneously, 75 structural genes that regulate PA biosynthesis were identified, of these 6 structural genes (IsF3′H1, IsANR2, IsLAR2, IsUGT72L1-3, IsMATE2, IsMATE3) may play an important role in the synthesis of PAs in I. stachyodes roots. Furthermore, co-expression network analysis revealed that 34 IsMYBs, 18 IsbHLHs, 15 IsWRKYs, 9 IsMADSs, and 3 IsWIPs hub TFs are potential regulators for PA accumulation. Among them, IsMYB24 and IsMYB79 may be closely involved in the PA biosynthesis in I. stachyodes roots. Conclusions The biosynthesis of PAs in I. stachyodes roots is mainly produced by the subsequent pathway of cyanidin. Our work provides new insights into the molecular pathways underlying PA accumulation and enhances our global understanding of transcriptome dynamics throughout different tissues.

Indigo Naturalis, also known as Qing Dai (QD) is a compound obtained from Indigofera tinctoria, Isatis tinctoria, and Polygonum tinctoria and is known to ameliorate refractory ulcerative colitis (UC) by an unknown mechanism. QD maintains both homeostasis and the integrity of colon epithelia in mice that have experimentally induced colitis. The primary component of QD, indigo, comprises 42.4% of the compound. Indigo efficiently suppresses rectal bleeding and reduces the erosion of the colon epithelium, whereas it does not reduce weight loss or increase survival in a certain condition. Indigo is a ligand of the aryl hydrocarbon receptor (AhR), which is involved in the anti-colitis activity of QD. Here we investigate the effects of indigo on wound (erosion) closure in colon epithelial cells. Oral administration of indigo induced expression of Cytochrome P450 1A1 (Cyp1a1) in the colon but not in the liver, suggesting that indigo stimulates AhR from the luminal side of the colon. The erosion-closure activity tested in the scratch assays using Caco-2 cells was accelerated by addition of QD and indigo to the culture medium. QD and indigo also induced nuclear localization of AhR and expression of CYP1A1 in the Caco-2 cells. Acceleration of scratch wound closure was abolished by addition of the AhR-antagonist CH223191. Cell proliferation and actin polymerization were also shown to contribute to erosion closure. The results suggest that indigo exerts its erosion-healing effects by increasing proliferation and migration of colon epithelial cells via activation of AhR in intestinal epithelia.

The emerging demand of natural indigo dye due to the environmental and sociological concerns imparted by the synthetic dye helps in leveraging the conventional natural indigo dye production process in many developing countries, including India. Despite having remarkable global market potential, the high price of natural indigo dye impedes its extensive commercialization. Therefore, in the present study, the economics of natural indigo dye is evaluated through life cycle cost (LCC) analysis by considering the traditional indigo dye production process in India using the plant biomass Indigofera tinctoria L. The life cycle model includes cultivation of Indigofera biomass, as well as the production and processing of indigo dye and the cost involved in each step. Along with the detailed cost analysis, the present study also includes socio-economic analysis and possibilities of cost reduction based on the outcome of sensitivity analysis. From the LCC analysis, the life cycle cost of Indigofera biomass cultivation is $420.74 ha−1 year−1, whereas the indigo dye production cost is $113 ton−1 of Indigofera biomass. For an annual dye production of 1000 tons, the present study estimated the economic stabilization of rural farmers and labours by an annual employment generation of 196,250 man-days year−1 and 12,50,000 man-days year−1, respectively. By sensitivity analysis, the raw material price was identified as the major contributor in the total indigo dye production cost. As a cost reduction measure, the combination of biomass yield (70 tons) and reduction in the biomass production cost (50%) was found to be suitable. Utilization of by-product generated from the dye industry into value-added products could contribute towards a cost reduction of 22% in the Indigofera biomass cultivation and a cost saving of $37.4 ton−1 of biomass in the indigo dye production cost.

The current study focuses on the valorization potential of Indigofera tinctoria L. waste biomass recovered from the indigo dye production process for biofuel and compost. In order to compare the potential of after dye extracted biomass (ADB) with before dye extracted biomass (BDB), different physical (proximate analysis, calorific value, thermo-gravimetric analysis (TGA), X-ray diffraction (XRD)), chemical (ultimate analysis, inorganic elemental analysis, Fourier transform infrared spectroscopy (FTIR)), and compositional characterization (cellulose, hemicellulose, lignin, and extractive content) were performed. With C/N ratio of 19.66 and high mineral contents (P = 1513.47 and K = 5672.63 ppm), ADB showed favorable potential for compost. Additionally, the ultimate composition (C = 44.23%, H = 6.62%, N = 2.25%, and O = 37.94%) and lignocellulosic composition (cellulose = 41.15%, hemicellulose = 28.9%) of ADB indicated comparable methane (498.94 L/kg VS) and ethanol (281.9 L/Mg) potential. Considering the overall biomass potential, an integrated approach has been suggested to utilize ADB for biofuels (biogas and bioethanol) and compost production. This approach may enhance the eco-sustainability by substituting the current energy and fertilizer need in Indigofera biomass cultivation and indigo dye production processes with a predicted energy equivalent of 3709.68 MJ (from biogas) or 1131.56 MJ (from bioethanol) per 240 kg dry weight of ADB.

High-performance liquid chromatography coupled to a diode-array detector (HPLC-DAD) is used to investigate 30 samples which were removed from 27 ancient Egyptian fabrics of the Fill-Trevisiol collection. Attention is focused in this paper on fabrics of the Roman and Byzantine periods, with red and deep violet–blue wool weft threads which are Z-spun. The following dyes are identified in fabrics which date to the Roman period (first–fifth c. ad): mollusc purple, madder, and indigo/woad (Indigofera species and other, Isatis tinctoria L.). The results for the Byzantine (fifth–seventh c. ad) fabrics are richer in terms of identified dyes: apart from the three aforementioned dyes, the use of kermes (Kermes vermilio Planchon) and cochineal is revealed as the two coccid dyes have been detected in six Egyptian–Byzantine fabrics. Moreover, a yellow dye (probably Reseda luteola L.) is identified in one sample. Finally, samples taken from two fabrics, which date to the Islamic period, were dyed using indigo/woad and lac (Kerria lacca, Kerr). Mixing madder and indigo/woad to imitate true purple was a common practice in ancient Egypt and this is confirmed by the HPLC results in several samples. Semi-quantitative results are obtained from the HPLC peak areas and lead to the following conclusions. Madder dyes which were rich or poor in alizarin, compared to purpurin, and could have been therefore obtained from Rubia tinctorum L. and Rubia peregrina L., respectively are detected in Byzantine fabrics. Only alizarin-rich madder dyes are identified in some samples from Roman fabrics, but in some other samples the relative alizarin-to-purpurin ratio cannot be measured with confidence. Cochineal is found in two samples. The biological source of cochineal (Porphyrophora hamelii Brandt) is possible to be chemically identified only in one sample. The HPLC results of the molluscan dye detected in a Roman fabric are compared with the relative compositions of extracts of the three Mediterranean molluscs leading to the speculation that the Roman purple sample was probably dyed using Hexaplex trunculus L. The molluscan dye was furthermore detected in a Byzantine sample where it was combined with madder. Finally, it is reported that the standard (hydrochloric) acid hydrolysis method which is commonly applied to extract dyes from archaeological samples does not have any noticeable effect on the relative composition of the molluscan dye.

Four new species of Indigofera (Leguminosae, Papilionoideae) for the flora of Mexico are described and illustrated: Indigofera floresii, I. hirsutissima, I. magallanesii and I. sinaloensis. Among the new species, I. sinaloensis, is the second species of the series Platycarpae. Including these four new species, we estimate the existence in Mexico of about 31 wild species of the genus.

Background Historically, indigo-yielding plant species were important cash crops from Central Asia to the southern United States and Central America. Indigo-dyed textiles were widely traded along the legendary Silk Road that linked China to Europe. Today, due to the labor-intensive nature of indigo extraction at the household level, lifestyle changes and the widespread availability of commercially produced indigo paste, traditional indigo extraction methods have declined in villages. Yet Li textile weavers on Hainan Island are internationally recognized as producers of indigo-dyed textile using warp ikat techniques. In contrast, Hainan Miao weavers produce indigo-dyed textiles using batik (wax resist) techniques. The aim of this study was to document the indigenous knowledge on indigo-yielding plant species used by both Hainan Miao and Li people on Hainan Island, China. Method Ethnic uses were documented during three field surveys, through a questionnaire survey of 193 respondents, comprising 144 Hainan Miao and 49 Li traditional dyers. Mention index (QI), Availability index (AI), and Preference ranking (PR) of each indigo-yielding plant species were calculated to screen out plant resources with potential development value. Results Five indigo-yielding plant species (from four plant families and four genera) were historically used by Hainan Miao and Li dyers. However, just four species are still in use. Strobilanthes cusia was the main indigo source for Hainan Miao dyers. Li dyers also commonly use Indigofera species (I. tinctoria and I. suffruticosa) for indigo extraction. Wrightia laevis is less commonly used as a contemporary indigo source. Indigo extraction by steeping in water to which lime is added to increase the pH is sharing by the five indigo-yielding plant species. Strobilanthes cusia had the highest QI, AI and PR values in Hainan Miao villages. Indigofera tinctoria had the highest QI and AI values, but Indigofera suffruticosa was preferred by Li dyers. Conclusion In the process of modernization and urbanization, some Hainan Miao and Li dyers retain the traditional indigo extraction methods. We found that Strobilanthes cusia and Indigofera tinctoria have the most potential for sustainable indigo production in the future. Furthermore, this study documents the details of extraction method from Wrightia laevis for the first time and the use of Ricinus communis seeds in that process. As one of the last places globally where Wrightia laevis is still used for indigo production, the may also be a nice market among textile collectors and museums that keeps the tradition of Wrightia laevis production and use for indigo extraction alive.

Asia, especially the temperate Sino-Himalayan region is one of the four major diversity centers of Indigofera. Pollen morphology of Indigofera species in the Sino-Himalayan region is poorly known. In this study, pollen morphology of 52 samples representing 43 Chinese Indigofera species and two varieties was examined using scanning electron microscopy to evaluate its taxonomic significance. Parasyncolpate pollen grains were described in Indigofera for the first time. Cluster and principal component analyses were conducted based on four quantitative and three qualitative pollen characters. Five groups were recognized within Chinese Indigofera in the cluster analysis, but only one can be separated by the first three principal components. The shape and size of pollen grains in Indigofera are highly variable. Consequently, both the characters lack any significant taxonomic value. The number of apertures, tectum architecture and perforation density shows some taxonomic significance. The pollen morphology exhibits obvious phylogenetic and biogeographical significance on large scales in Indigofera. Although pollen characters alone are insufficient to reconstruct the taxonomic relationships within Indigofera, palynological data can provide some useful information for the species-level revisions.

Natural indigo production from Indigofera plant biomass requires fermentation of biomass, oxidation of fermented broth, settling of oxidized product (indigo), filtration and recovery. In this study, we have investigated roles of physico-chemical parameters during fermentation with respect to product yield. The study showed that water-to-biomass ratio (1:10), fermentation duration (0, 6, 12, 18, 24 h), pH (6–7.5), dissolved oxygen concentration; DO (0.5–3 mg ml−1), oxidation reduction potential ORP (+50 to −300 mV) and temperature (25–40 °C) during fermentation, oxidation and dye recovery from the broth are directly or indirectly related to indigo yield. Biomass fermentation for 12 h at 40 °C incubation temperature yields the highest biogenic indigo (2.84 mg g−1) out of the different experimental conditions.

Background Indigo naturalis is a Traditional Chinese Medicine (TCM) ingredient long-recognized as a therapy for several inflammatory conditions, including psoriasis. However, its mechanism is unknown due to lack of knowledge about the responsible chemical entity. We took a different approach to this challenge by investigating the molecular profile of Indigo naturalis treatment and impacted pathways. Methods A randomized, double-blind, placebo-controlled clinical study was conducted using Indigo naturalis as topical monotherapy to treat moderate plaque psoriasis in a Chinese cohort (n = 24). Patients were treated with Indigo naturalis ointment (n = 16) or matched placebo (n = 8) twice daily for 8 weeks, with 1 week of follow-up. Results At week 8, significant improvements in Psoriasis Area and Severity Index (PASI) scores from baseline were observed in Indigo naturalis-treated patients (56.3% had 75% improvement [PASI 75] response) compared with placebo (0.0%). A gene expression signature of moderate psoriasis was established from baseline skin biopsies, which included the up-regulation of the interleukin (IL)-17 pathway as a key component; Indigo naturalis treatment resulted in most of these signature genes returning toward normal, including down-regulation of the IL-17 pathway. Using an in vitro keratinocyte assay, an IL-17-inhibitory effect was observed for tryptanthrin, a component of Indigo naturalis. Conclusions This study demonstrated the clinical efficacy of Indigo naturalis in moderate psoriasis, and exemplified a novel experimental medicine approach to understand TCM targeting mechanisms. Trial registration NCT01901705. Electronic supplementary material The online version of this article (10.1186/s12906-017-1947-1) contains supplementary material, which is available to authorized users.

During the present study, 360 populations of 174 species belonging to 82 genera and 23 families of dicots have been cytologically worked out from different localities of District Kangra (Himachal Pradesh) between 550 and 3,800 m altitude. As many as 10 species including Berberis ceratophylla (2n = 28), Caltha alba (2n = 32), Corydalis meifolia (2n = 16), C. thyrsiflora (2n = 16), Impatiens reidii (2n = 14), Indigofera hamiltonii (2n = 16), Potentilla thomsonii (2n = 14), Sedum trifidum (2n = 36), Stellaria semivestita (2n = 26) and Viola canescens (2n = 12) have been cytologically worked out for the first time at world level. New intraspecific diploid cytotypes have been recorded in 11 species while new intraspecific tetraploid cytotypes are noticed in 15 species. B-chromosomes have also been reported in 3 species viz. Anemone obtusiloba, Clematis grata and Ranunculus diffusus for the first time at world level. The species of the area are active state of evolution, depicting heterogeneity in chromosome numbers involving polyploidy (48 species, 28.18 %) as well as irregular meiotic behavior. The meiotic abnormalities have been witnessed in 69 species (39.65 %) showing different types of irregularities such as cytomixis, interbivalant connections, unoriented bivalents, chromatin stickiness, chromosomal laggards and bridges as well as abnormal microsprogenesis. All these meiotic abnormalities lead to reduced pollen fertility and formation of variable sized pollen grains in most of these species.

Background Till now many of medicinal plants having claimed therapeutic value traditionally are waiting scientific verification of their efficacy and safety. Accordingly this study is conducted to evaluate the antidiarrheal activity of hydromethanolic root extract of Indigofera spicata Forssk. in castor oil induced diarrhea model, misoprostol induced secretion model and its antimotility activity using charcoal as a marker. Methods In all the three models the animals were randomly allocated into five groups of six animals each and then group I mice were received 1 ml/100 g normal saline, group II were treated with standard drug as a positive control whereas group III, IV and V were treated with 100, 200 and 400 mg/kg extract doses, respectively. Statistical significance of differences in the mean of number of defecations, fluid content of faces, intestinal fluid accumulation ratio, intestinal fluid weight and distance travelled by charcoal between groups was analyzed by SPSS version-21 using one way ANOVA followed by Tukey’s post hoc multiple comparison. Result The hydromethanolic crude extract of Indigofera spicata at 200 and 400 mg/kg mg/kg doses showed statistically significant (p

Inflorescence and floral development of three species of Indigofera (Leguminosae-Papilionoideae), I. lespedezioides, I. spicata, and I. suffruticosa, were investigated and compared with that of other papilionoid groups, especially with members of the recently circumscribed Millettioid clade, which was merged as sister to Indigofereae in a recent cladistic analysis. Although Indigofera is a genus of special interest, because of its great richness in species and its economic importance, few studies have been made of floral development in the genus or in Indigofereae as a whole. Flower buds and inflorescences were analysed at several stages of development in the three species. Our results confirmed that Indigofera species bear a usual inflorescence type among legumes, the raceme, which comprises flowers initiated in acropetal succession, each with a subtending bract and no bracteoles initiated. The inception of the floral organs is as follows: sepals (5), petals (5), carpel (1), outer stamens (5), and, finally, inner stamens (5). Organ initiation in the sepal, petal, and both stamen whorls is unidirectional, from the abaxial side; the carpel cleft is adaxial. The vexillum is larger than other petals at maturity, covering the keels, which are fused edge-to-edge. Nine filaments are fused to form an adaxially open sheath, and the adaxial stamen of the inner whorl remains free (diadelphous androecium) in the mid-stage of development. Most of the infra-generic differences occurred in the later stages of development. Data on floral development in Indigofera obtained here were also compared with those from other members of Papilionoideae. This comparison showed that the early expression of zygomorphy is shared with other members of the Millettioid clade but is rarely found in other papilionoids, corresponding to a hypothetically morphological synapomorphy in the pair Indigoferae plus millettioids.

Two new flavonol glycosides were isolated from the 1-butanol (1-BuOH)-soluble fraction of a methanol (MeOH) extract of the leaves of Indigofera zollingeriana, along with four flavonol glycosides and three known megastigmane glucosides. The structures of the new compounds were elucidated by spectroscopic analyses as kaempferol 3-O-β-D-(2"-O-β-D-apiofuranosyl)glucopyranoside 7-O-α-L-rhamnopyranoside and 3-O-β-D-(2"-O-β-D-apiofuranosyl, 6"-O-α-L-rhamnopyranosyl)glucopyranoside 7-O-α-L-rhamnopyranoside.

Abundance of Fabaceae declines in representation through post-fire-succession in fynbos vegetation of the Cape Floristic Region (CFR). This reduction in legume occurrence coincides with a known decline in post-fire soil P availability. It was hypothesized that the disappearance of legume species during post-fire succession is due to an inability to acquire P effectively from sparingly soluble sources. P-acquisition strategies and response to P supply were compared between legume (Aspalathus, Cyclopia, Indigofera, Podalyria) and non-legume (Elegia, Leucadendron, Protea) genera when supplied with 1 or 10 mg P kg−1 dry sand. Each genus consisted of a seeder (non-persistent) and resprouter (persistent) species. Non-legumes showed a greater investment in below-ground biomass, more root clusters, with higher concentrations of carboxylates exuded by cluster roots and carboxylates that were better suited to the mobilization of sparingly soluble P compared to legumes. The growth response to increased P supply was 53% higher in legumes than in non-legumes. The lack of a growth response to an elevated P supply in the non-legumes was attributed to N-limitation. Legume resprouters had a higher investment in cluster-root biomass and a lower capacity to down-regulate P-uptake than the seeders. Therefore the inability to acquire sufficient P from low concentration and sparingly soluble soil P-sources may contribute to the lack of indigenous legume persistence in fynbos vegetation of the CFR.

In vitro axillary shoot proliferation was achieved from single-node explants of Indigofera tinctoria on a well-defined medium, Murashige and Skoog (MS) medium supplemented with 1.0 mg l−1 N 6-benzyl adenine (BA) and 0.1 mg l−1 indole-3-acetic acid. Axillary shoot meristems from cultures derived from up to three subcultures were used in the encapsulation–dehydration technique. Preconditioned, calcium alginate-encapsulated, and precultured axillary shoot meristems were subjected to different lengths of desiccation in a laminar flow cabinet. Maximum survival and regeneration rates of 56.7% and 62.2%, respectively, were obtained in half-strength (half the macro- and micronutrients and full-strength vitamins) MS medium supplemented with 0.5 mg l−1 gibberellic acid and 0.2 mg l−1 BA after 4 h of desiccation, during which the moisture content was reduced to 16.0%. According to the analysis of six random amplified polymorphic DNA markers, plantlets derived from cultures initiated with cryopreserved plant material were genetically identical to those derived from nonfrozen (control) tissues.

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.

Background Diabetes mellitus is found in all parts of the world and is rapidly increasing in its coverage with alarming rate especially in Asia and Africa. Research is increasingly done with the aim of developing a relatively safe and efficacious anti-diabetic plant based products. Parallelly, this investigation was carried out to evaluate the effect of the hydro alcoholic leaves crude extract of Indigofera spicata (ISP) on the blood glucose level(BGL) of normoglycemic, oral glucose loaded and alloxan induced diabetic rodents. Methods The animals were randomly divided into five groups (n = 6) for all the aforementioned three models. In all models, group-I mice provided 2%tween-80, group-II were treated with 5 mg/kg glibenclamide and the remaining three groups (III, IV & V) were treated with 100, 200, and 400 mg/kg dose of the extract respectively. Statistical significance of differences in BGLs within and between groups was analyzed by SPSS version-21 using one way ANOVA followed by Tukey’s post hoc multiple comparison. Result 200 mg/kg and 400 mg/kg extract treated groups of normoglycemic mice showed significant (p

Lack of synchronization between N released from prunings applied to the soil as green manures and crop uptake as well as optimization of protein digestibility for ruminants, remain major research objectives for the selection of multipurpose tree and shrub legumes (MPT) for mixed smallholder systems in the tropics. Prunings of the high tannin, low quality MPT Calliandra houstoniana CIAT 20400 (Calliandra) and the tannin free, high quality MPT Indigofera zollingeriana (Indigofera) were mixed in the proportions 100:0, 75:25, 50:50, 25:75, and 0:100 (w/w) in order to measure the aerobic rate and extent of N release in a leaching tube experiment, and the anaerobic extent of N degradation in an in vitro gas production experiment. Parameters measured in Calliandra:Indigofera mixtures were compared to theoretical values derived from single species plant material (i.e. 100:0 and 0:100). Aerobic N release and apparent anaerobic N degradation increased with increasing proportion of the high quality legume (Indigofera) in the mixture. While N release in the soil was lower than theoretical values in the mixture 50% Calliandra/50% Indigofera, this was not the case with apparent anaerobic N degradation with the same mixture. Aerobic N immobilization was more pronounced for the mixture 75% Calliandra/25% Indigofera than for 100% Calliandra and negative interaction was observed with apparent anaerobic N degradation in the mixture 75% Calliandra/25% Indigofera. Plant quality parameters that best correlated with aerobic N release and apparent anaerobic N degradation in the rumen were lignin + bound condensed tannins (r=−0.95 and −0.95 respectively, P

Indigin, alkylated xanthene (1) and indigoferic acid (2) have been isolated from the chloroform soluble fraction of Indigofera oblongifolia, along with beta-sitosterol (3) and 3-hydroxybenzoic acid (4), which are reported for the first time from this species. Their structures were determined through spectroscopic techniques. Both the new compounds 1 and 2 showed significant activity against enzyme lipoxygenase, while 2 further showed moderate inhibition against BChE.

Planted fallow systems under ‘slash and mulch’ management were compared with natural fallow systems at two farms (BM1 and BM2) in the Colombian Andes. The BM1 site was relatively more fertile than the BM2 site. Planted fallow systems evaluated included Calliandra calothyrsus CIAT 20400 (CAL), Indigofera constricta (IND) or Tithonia diversifola (TTH). During each pruning event slashed biomass was weighed, surface-applied to the soil on the same plot and sub-samples taken for chemical analyses. While Indigofera trees consistently showed significantly greater (p < 0.05) plant height and collar diameter than Calliandra trees at both study sites, only collar diameter in Indigofera was significantly affected at all sampling times by differences between BM1 and BM2. After 27 months, TTH presented the greatest cumulative dry weight biomass (37 t ha–1) and nutrient accumulation in biomass (417.5 kg N ha–1, 85.3 kg P ha–1, 928 kg K ha–1, 299 kg Ca ha–1 and 127.6 kg Mg ha–1) among planted fallow systems studied at BM1. Leaf biomass was significantly greater (P < 0.05) for CAL than IND irrespective of site. However, CAL and IND biomass from other plant parts studied and nutrient accumulation were generally similar at BM1 and BM2. At both sites, NAT consistently presented the lowest biomass production and nutrient accumulation among fallow systems. Planted fallows using Calliandra and Indigofera trees had the additional benefit of producing considerable quantities of firewood for household use.

The decomposition and nutrient release of 12 plant materials were assessed in a 20-week litterbag field study in hillsides from Cauca, Colombia. Leaves of Tithonia diversifolia (TTH) and Indigofera constricta (IND) decomposed quickly (k=0.035±0.002 d−1), while those of Cratylia argentea (CRA) and the stems evaluated decomposed slowly (k=0.007±0.002 d−1). Potassium presented the highest release rates (k>0.085 d−1). Rates of N and P release were high for all leaf materials evaluated (k>0.028 d−1) with the exception of CRA (N and P), TTH and IND (P). While Mg release rates ranged from 0.013 to 0.122 d−1, Ca release was generally slower (k=0.008–0.041 d−1). Initial quality parameters that best correlated with decomposition (P>0.001) were neutral detergent fibre, NDF (r=−0.96) and in vitro dry matter digestibility, IVDMD (r=0.87). It is argued that NDF or IVDMD could be useful lab-based tests during screening of plant materials as green manures. Significant correlations (P>0.05) were also found for initial quality parameters and nutrient release, being most important the lignin/N ratio (r=−0.71) and (lignin+polyphenol)/N ratios (r=−0.70) for N release, the C/N (r=0.70) and N/P ratios (r=−0.66) for P release, the hemicellulose content (r=−0.75) for K release, the Ca content (r=0.82) for Ca release, and the C/P ratio (r=0.65) for Mg release. After 20 weeks, the leaves of Mucuna deerengianum released the highest amounts of N and P (144.5 and 11.4 kg ha−1, respectively), while TTH released the highest amounts of K, Ca and Mg (129.3, 112.6 and 25.9 kg ha−1, respectively). These results show the potential of some plant materials studied as sources of nutrients in tropical hillside agroecosystems.

Background The Fabaceae family is the second largest family of medicinal plants, containing more than 490 species which are being used as traditional medicine. The aim of this study was to determine the antioxidant and antibacterial activity as well as the cytotoxicity of acetone leaf extracts of nine tree species from the Fabaceae family that have not been investigated well previously for possible use in animal health and production. Methods The antibacterial activity was determined by a serial microdilution method against three Gram-positive and three Gram-negative bacteria. Antioxidant activity was determined using free-radical scavenging assays. The safety of the extracts was ascertained using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on Vero African green monkey kidney cells. Results Six of the nine acetone extracts had significant antibacterial activity against at least one of the six bacterial species with (MIC 20–80 μg/mL). The Crotalaria capensis extract had the highest activity against Salmonella typhimurium, followed by Indigofera cylindrica with MICs of 20 μg/mL and 40 μg/mL respectively. The Dalbergia nitidula extract had free radical scavenging capacity (IC50 of 9.31 ± 2.14 μg/mL) close to that of the positive control Trolox in the DPPH assay. The Xylia torreana extract also had high activity (IC50 of 14.56 ± 3.96 μg/mL) in the ABTS assay. There was a good correlation between antioxidant activity and total phenolic content (R2 values > 0.8). The extracts had weak or no toxicity to Vero cells, compared to the positive control doxorubicin with the LC50 varying from 10.70 ± 3.47 to 131.98 ± 24.87 μg/mL at the concentrations tested. Conclusion Extracts of D. nitidula, X. torreana, C. capensis and I. cylindrica had a low cytotoxicity and high antimicrobial and/or antioxidant activity. These species are therefore promising candidates for the development of useful antimicrobial/antioxidant preparations with a low cytotoxicity that may be useful in promoting animal health and productivity.

A eubacterium producing a blue pigment was isolated from a drinking water filter, and subsequently identified as Vogesella indigofera. This bacterium was further investigated for its morphological and biochemical characteristics after exposure to hexavalent chromium, Cr6+. The threshold Cr6+ concentration inhibiting the pigment production by V. indigofera was 200–300 μg ml−1 in liquid cultures of nutrient broth and 100–150 μg ml−1 on nutrient agar plates. The Cr6+ concentration preventing V. indigofera growth was 300–400 μg ml−1 in liquid cultures, but greater than 150 μg ml−1 on agar plates. Moreover, rugose colonies without the blue pigmentation were observed on agar plates amended with 150 (μg Cr6+) ml−1. The biochemical utilization profiles of the colonies without pigmentation did not differ from the original pigment-producing ones, indicating phenotypic plasticity of this bacterium. The difference of phenotypic expression of V. indigofera under various Cr6+ concentrations might have potential application as a pollution bioindicator for heavy metals.

Several legume-Rhizobium associations were evaluated by sowing and broadcast of seeds encapsulated with polyacrylamide-entrapped rhizobia (PER) in an opencast limestone quarry in the outer ranges of the Himalaya. Four wild legumes, Lespedeza stenocarpa, Astragalus graveolens, Argyrolobium flaccidum and Indigofera gangetica, with various rhizobial strains, showed higher seedling establishment and survival as well as higher biomass than controls (uninoculated treatments). All legumes established without aftercare. Both A. flaccidum and L. stenocarpa flowered and fruited and the self sown seeds of the experimental stands of the latter species also germinated. Within four years following seeding, many non-legumes colonized the experimental site indicating the amelioration of the derelict habitat. These results give evidence that novel, suitable wild legume-Rhizobium associations are useful in providing a vegetational cover in degraded lands, and that the ecological restoration of limestone-mined sites are possible to some extent by artificial reconstruction. Nodulation in inoculated treatments only suggests that revegetation programmes involving legumes should also include their microsymbionts. Results also suggest that the encapsulation of seeds with PER is a suitable inoculation technology for the revegetation programmes.

alogy and acidity, biological activity, and the presence of other nutrients (Myers et al., 1994). In a previous For legume green manures (GM) to be effective, environmentally study, 60-d-old soybean [Glycine max (L.) Merr.] and sound N sources for horticultural crops in the tropics, their N release indigofera (Indigofera tinctoria L.) plants conformed to must be in synchrony with crop N demand. Decomposition and N high-quality litter characteristics (Swift, 1987), releasing release of surface applied (mulch) or incorporated soybean [Glycine §

Structure and distribution patterns of the trichomes occurring on the standard petals in 8 species ofIndigofera L. have been investigated. In all, 4 trichome types exhibiting 7 distribution patterns have been recognised. Their taxonomic significance has been shown by providing a key for the identification of the species studied.

The distribution pattern of phenolic constituents in 8 species ofIndigofera is studied. There is uniform occurrence ofp-coumaric,p-OH benzoic and vanillic acids and an unknown phenolic compound ‘e’ of hRf value 42/57 in all the taxa studied. There is a chemical similarity betweenIndigofera hochstetteri andIndigofera tinctoria. Indigofera dalzellii, Indigofera hirsuta, Indigofera oblongifolia andIndigofera prostrata stand out in the unique possession of certain compounds. The overlapping incidence of the constituents indicates the fairly close chemical ties among the species studied. The cluster analysis reveals that it supports earlier sub divisions of the genus to some extent.

Leaf tissue of four representative species from a limestone-sandstone transition, together with their respective soils, were analysed for cations. The species studied comprisedLeucospermum cuneiforme (Proteaceae) from the acid sandstone,Indigofera sp. nov. (Fabaceae) from the base-rich limestone,Elytropappus rhinocerotis (Asteraceae) from the transition zone andDodonaea angustifolia (Sapindaceae) which occured on all three substrates.

Although the ancient Briton's woad, from Isatis tinctorio L., has been differentiated from the indigo dye indoxyl-β-D-glucoside, from the tropical legume genus Indigofera, it has never been identified. It has now been shown to be indoxyl-5-ketogluconate and its structure is completely specified.

This report includes: a new variety,Indigofera miniata var.florida, and five new combinations.I. mucronata var.keyensis, Robinia hispida var.kelseyi, Tephrosia angustissima var.corallicola, T. angustissima var.curtissii, andT. × floridana.

IT may be of interest to Mr. Alexander Nelson and to other readers of NATURE (Dec. 4, 1926, p. 804) to know that sulphuric acid has been used industrially for the promotion of germination in hard leguminous seeds for some years. The substitution on an extensive scale of Indigofera arrecta for the previously cultivated Indigofera sumatrana by the indigo planters of Bihar during the early years of the century was, in fact, made possible largely by the introduction of the sulphuric acid method of seed treatment into their agricultural practice. The seed of Indigofera arrecta grown in Bihar was found to possess a very hard coat and to fail to germinate almost entirely under the conditions of soil moisture prevailing in northern India. Treatment with sulphuric acid led to perfect germination in a well-ripened sample of seed, and the method was used for many years and is, I believe, still used by the Bihar planters. The procedure differs slightly, however, from that indicated by Mr. Nelson in that concentrated, instead of dilute, acid is employed. A full description of the method as used in Bihar may be found in my report to the Bihar Indigo Planters' Association for the year 1906–7.