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The effects of different drying methods (freeze- and spray-drying) and carriers (gum Arabic and inulin) on the powder characterization and stability of the bioactive compounds of Hibiscus acetosella extract (HAE) during storage were evaluated. The 1H NMR spectrum of the HAE revealed characteristic signals of the caffeoyl hydroxycitric acid. The encapsulated extract powder presented different morphology according to the drying processes. The powders produced by the freeze-drying process presented higher retention of bioactive compounds due to the low temperature process. The mixture of gum Arabic and inulin as carrier resulted in the absorption of larger amount of water. The half-life time of the encapsulated extract powders ranged from 31 to 36 h (DPPH) and from 34 to 71 h (phenolic compounds). In general, the powders constituted of gum Arabic and recovered by the freeze-drying process presented better protection and retention of the bioactive compounds from the HAE.

Objective: Hibiscus acetosella (HA) or Chaba Maple is native plant and cultivated in tropical western in Africa and north of America. The characteristicsof HA are red to purple in stem, leaf, and flower that are the pigment of antioxidant compound as anthocyanins. Anthocyanins are in the groupof flavonoid and have the role as functional foods which have several health benefits such as obesity and diabetes control, cardiovascular diseaseprevention, and others. Hence, the aim of this study was to investigate the antioxidant and free radical scavenging activity of HA leaves extracts.Materials and Methods: HA (Chaba Maple) leaves were collected in Pathum Thani province, Thailand, and were dried and extracted by macerationtechnique with three solvents – water, ethanol, and methanol. The antioxidant properties of extracts were carried out using 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and ferric reducing antioxidant power (FRAP) assay. The extracts wereexamined for their scavenging effect on hydroxyl radical (•OH) using hydroxyl radical scavenging assay and nitric oxide (NO) radical (•NO) using NOradical scavenging assay.Results: For ABTS, FRAP, and hydroxyl radical scavenging assay, ethanol extract showed the highest antioxidant property which the percentageinhibitions were 69.04%, 2381.84 μM/mg extract, and 62.88 mg/ml, respectively. For NO scavenging activity, methanol extract showed highest abilityto scavenge NO which percentage inhibition was 101.28±0.73 mg/ml.Conclusion: The results of this study showed that ethanolic, methanolic, and water extract of HA leaves had scavenge and reducing antioxidantproperties.

Phenolic compounds are a large group of phytochemical compounds in plants which have antioxidant activity. Hibiscus species were used in traditional medicine in North-America with biological activities. In this study, total phenolic content, total flavonoid content and antioxidant activities of Chaba maple (Hibiscus acetosella) flower extract (CFE) in Thailand were investigated. The total phenolic and flavonoid contents were determined by Folin-Ciocalteu assay and aluminum chloride colorimetric method, respectively. Antioxidant activities of CFE were examined by DPPH radical scavenging, ferric reducing antioxidant power (FRAP) and nitric oxide (NO) radical scavenging ability methods. The results showed that total phenolic content and total flavonoid content were 91.22±0.68 mg gallic acid equivalent/g fresh matter and 0.31±0.01 mg quercetin equivalent/g fresh matter, respectively. For antioxidant activities, IC50 of DPPH radical scavenging was 57.93±0.37 μg/ml, the power of ferric reducing was 1,707.18±1.99 μM and IC50 of NO radical scavenging was 229.30±0.71 μg/ml. In conclusion, CFE could be potentially used as a new natural bioactive ingredient for nutritional supplements and cosmetics application.

Hibiscus species are rich in phenolic compounds and have been traditionally used for improving human health through their bioactive activities. The present study investigated the phenolic compounds of leaf extracts from 18 different H. acetosella accessions and evaluated their biofunctional properties, focusing on antioxidant and antibacterial activity. The most abundant phenolic compound in H. acetosella was caffeic acid, with levels ranging from 14.95 to 42.93 mg/100 g. The antioxidant activity measured by the ABTS assay allowed the accessions to be classified into two groups: a high activity group with red leaf varieties (74.71&ndash, 84.02%) and a relatively low activity group with green leaf varieties (57.47&ndash, 65.94%). The antioxidant activity was significantly correlated with TAC (0.933), Dp3-Sam (0.932), Dp3-Glu (0.924), and Cy3-Sam (0.913) contents (p &lt, 0.001). The H. acetosella phenolic extracts exhibited antibacterial activity against two bacteria, with zones of inhibition between 12.00 and 13.67 mm (Staphylococcus aureus), and 10.67 and 13.33 mm (Pseudomonas aeruginosa). All accessions exhibited a basal antibacterial activity level (12 mm) against the Gram-positive S. aureus, with PI500758 and PI500764 exhibiting increased antibacterial activity (13.67 mm), but they exhibited a more dynamic antibacterial activity level against the Gram-negative P. aeruginosa.

Twenty one (21) traditional food plants recognized as medicinal by communities in Kamuli and Gulu districts in Uganda were identified and analyzed for their phytochemical content and antioxidant activity. The total phenolic content (2.6 ± 0.1 to 184.2 ± 6.4 mg GAE gDW-1) and flavonoid content (0.3 ± 0.1 to 162.2 ± 3.5 mg CE gDW-1) as well as antioxidant activity (0.1 ± 0.1 to 57.8 ± 0.5 mg VCE gDW-1) varied widely among the food plants. The seeds of Tamarindus indica L. and leaves of Ipomea eriocarpa R.Br., Corchorus trilocularis L., Ocimum suave L., Corchorus olitorius L., Acalypha bipartita Mull.Arg., and Hibiscus acetosella Welw. ex Hiern showed the highest phenolic contents and antioxidant activities. Juice prepared from tamarind pulp alone or mixed with tamarind seed powder (0.5, 1 and 3%) and analyzed for sensory acceptability, phenolic content and anti-oxidant activity were found to be highly acceptable, recording an overall hedonic acceptability scores of 7.40 ± 0.4, 6.65 ± 0.3, 7.01 ± 0.1 and 5.34 ± 0.2, respectively on a nine-point scale for juice containing 0, 0.5, 1 and 3% seed powder. Incorporation of tamarind seed powder into tamarind pulp juice resulted in a dose dependent increase in antioxidant activity from 8.5 ± 0.2 mg VCE 100 ml-1 for the control to 12.05 ± 0.3, 15.33 ± 0.7 and 17.22 ± 0.7 mg VCE 100 ml-1 for tamarind juice containing 0.5, 1 and 3% seed powder, respectively. A similar trend was recorded for the total phenolic and flavonoids. Key words: Medicinal foods, nutraceuticals, antioxidant activity, phenolics, flavonoids.

Methanolic and dichloromethane extracts from the leaves of Congolese Hibiscus species were characterised by chromatographic and spectroscopic techniques and their in vitro biochemical activities against ROS production were evaluated in cellular models and on an enzyme, myeloperoxidase (MPO), involved in inflammation. Hibiscus acetosella has a chemical fingerprint different from Hibiscus cannabinus and Hibiscus sabdariffa both having similar fingerprints. Major compounds were polyphenols, represented mainly by caffeoyl-hydroxycitric acid for H. acetosella and neochlorogenic acid for the two other species. All extracts displayed high cellular antioxidant activity with IC50 values ranging from 0.5 to 3 μg mL−1 using lucigenin on neutrophils. Dichloromethane extracts showed more efficient effects on extracellular ROS production and MPO activity. Antioxidant and anti-inflammatory activities of caffeoyl-hydroxycitric acid were significantly higher than those of neochlorogenic acid. The bioactivities of Hibiscus species were positively correlated with their phytochemical content and could justify their use as local nutraceutical resources and medicines.

The major anthocyanin pigments extracted from Hibiscus acetosella flower were investigated by UV–Vis spectroscopy and multivariate curve resolution-alternating least squares (MCR-ALS). Pure spectra and kinetic of the species present at different pH values were recovered for anthocyanins transformation and degradation products, found with and without UV radiation exposure. In the absence of UV radiation, up to seven different species were detected and by UV radiation exposure, this number increased to up to nine. The species detected in the absence of radiation were also detected when pigments samples were exposed to UV radiation, where degradation occurred faster and two new species appear. The kinetic profiles obtained at different pH values allowed the proposal of a reaction mechanism and pathway.

Seeds of Hibiscus dasycalyx S. F. Blake and Shiller, a federally listed candidate endangered species and native to North America and two variants of Hibiscus acetosella Welw. ex. Hiern were scarified using sulfuric acid and hot water. The effects of the scarification methods on in vitro and ex vitro germination in both species were evaluated. Sulfuric acid scarification was very effective for in vitro and ex vitro germination of both forms of H. acetosella and H. dasycalyx seeds by dramatically increasing germination rate and decreasing germination time. Acid scarification of H. acetosella seeds for 10, 15, or 20 min resulted in close to 90% germination within a week. Germination rates of about 70% (ex vitro) and 80% (in vitro) were obtained in H. dasycalyx seeds treated with sulfuric acid. Germination rates of 54% (ex vitro) and 95% (in vitro) were achieved when H. dasycalyx seeds were treated with hot water for 5 min, but exposing the seeds for 10, 15, or 20 min produced poor results in H. acetosella and H. dasycalyx as hot water scarification appeared to result in severe injury or death of the embryos. The protocols described here constitute rapid, reliable and simple methods to germinate H. acetosella and H. dasycalyx seeds in vitro and ex vitro. These results can be valuable in commercial productions or research projects. In addition, the in vitro germination of H. dasycalyx can offer a valuable tool in conservation efforts for this threatened species.

Hibiscus acetosella Welw. ex Hiern. ‘Panama Red’ PP20,121 (Malvaceae) has generated public and grower interest due to its attractive red foliage and vigorous growth, however, a horticultural goal is to develop more compact forms. Even though organs of induced polyploids are often larger than the wild type, whole plants are often shorter in stature. Three studies were conducted to induce polyploidy and to evaluate the growth and reproductive potential of the resulting polyploids. In study 1, seeds were soaked for 24 hours in aqueous solutions of 0%, 0.2%, 0.4%, or 0.5% colchicine (w/v) plus 0.5% dimethyl sulfoxide. In studies 2 and 3, apical meristems of seedlings at the cotyledon stage were treated for 1 or 3 days with 0, 50, 100, or 150 μm oryzalin solidified with 0.8% agar. Visual observations and measurement of guard cells were used to identify plants that potentially had their chromosome number doubled. Flow cytometry of nuclei stained with DAPI was used for confirmation of polyploidy. No induced polyploidy was observed following seed treatment with colchicine at the rates and duration used in this study. One-time application of 50 μm oryzalin resulted in a single mixoploid (4x + 8x) in which the ploidy of the L-I, L-II, and L-III histogenic layers were identified as a 4–4-4 + 8, respectively. Three-day applications with 100 and 150 μm oryzalin resulted in an octoploid (8x) and a mixoploid (4x + 8x), respectively. The mixoploid from the 3-day treatment stabilized at the 8x level before flowering, but was identified as a 4 + 8-x-4 cytochimera. Plant height was reduced, leaves were smaller, internodes were shorter, and canopy volume was reduced in the octoploid (8x) form compared with the tetraploid (4x) form. Furthermore, in contrast to the tetraploid, the octoploid produced no self-pollinated seed and performed poorly as a staminate and pistillate parent in controlled crosses. This represents the first time oryzalin has been reported to induce polyploidy in Hibiscus L. section Furcaria DC. H. acetosella is an allotetraploid species with the genome composition AABB. The resulting autoallooctoploid (AAAABBBB) form of ‘Panama Red’ exhibits a more compact habit and reduced production of seed.

Mature seeds of diploid and tetraploidHibiscus species were analyzed for enzyme activity (alcohol dehydrogenase, malate dehydrogenase, leucine aminopeptidase), total protein content, DNA amount and dry weight. The recently formed tetraploid,H. radiatus, generally had enzyme and protein levels very similar to the sum of its progenitors, while the more ancient speciesH. acetosella had several lower levels. This difference may reflect the greater amount of timeH. acetosella has had to evolve dosage compensations.

Hibiscus acetosella was shown to exert beneficial effects in humans and animal models however, the effects of this plant on DNA are unknown. The aim of this study was to determine the antigenotoxic and antimutagenic effects of H. acetosella extracts on alkylating agent methyl methanesulfonate (MMS) in vivo in mice. Initially, we performed analysis of phenolic compounds in extracts of H. acetosella by high-performance liquid chromatography (HPLC). Next, mice were divided into 8 groups and treated with distilled water or plant extract (0.1 ml/10 g) by gavage for 15 days, followed by intraperitoneal (ip) administration of saline solution or MMS (40 mg/Kg b.w) on day 16. Caffeic acid, following by gallic acid, gallocatechin, coumaric acid, and 3,4-dihydroxybenzoic acid were found to be present in extracts of H. acetosella leaves. In peripheral blood analysis of groups receiving pretreatment with H. acetosella at doses of 50 or 100 mg/kg plus MMS decreased DNA damage as evidenced by comet assay and Micronucleus assays relative to MMS alone. These results suggested that H. acetosella extracts exerted protective effects dose dependent against genotoxicity and mutagenicity induced by alkylating agents.