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Introduction: In obese humans, Coleus forskohlii root extract (CF) protects against weight gain owing to the presence of forskolin, an adenylate cyclase (AC) activator. As AC increases intracellular cyclic adenosine monophosphate (cAMP) levels in osteoblasts that has an osteogenic effect, we thus tested the skeletal effects of a standardized CF (CFE) in rats., Methods: Concentrations of forskolin and isoforskolin were measured in CFE by HPLC. CFE and forskolin (the most abundant compound present in CFE) were studied for their osteogenic efficacy in vitro by alkaline phosphatase (ALP), cAMP and cyclic guanosine monophosphate (cGMP) assays. Femur osteotomy model was used to determine the osteogenic dose of CFE. In growing rats, CFE was tested for its osteogenic effect in intact bone. In adult ovariectomized (OVX) rats, we assessed the effect of CFE on bone mass, strength and material. The effect of forskolin was assessed in vivo by measuring the expression of osteogenic genes in the calvarium of rat pups., Results: Forskolin content in CFE was 20.969%. CFE increased osteoblast differentiation and intracellular cAMP and cGMP levels in rat calvarial osteoblasts. At 25 mg/kg (half of human equivalent dose), CFE significantly enhanced calcein deposition at the osteotomy site. In growing rats, CFE promoted modeling-directed bone formation. In OVX rats, CFE maintained bone mass and microarchitecture to the level of sham-operated rats. Moreover, surface-referent bone formation in CFE treated rats was significantly increased over the OVX group and was comparable with the sham group. CFE also increased the pro-collagen type-I N-terminal propeptide: cross-linked C-telopeptide of type-I collagen (PINP : CTX-1) ratio over the OVX rats, and maintained it to the sham level. CFE treatment decreased the OVX-induced increases in the carbonate-to-phosphate, and carbonate-to-amide-I ratios. CFE also prevented the OVX-mediated decrease in mineral crystallinity. Nanoindentation parameters, including modulus and hardness, were decreased by OVX but CFE maintained these to the sham levels. Forskolin stimulated ALP, cAMP and cGMP in vitro and upregulated osteogenic genes in vivo ., Conclusion: CFE, likely due to the presence of forskolin displayed a bone-conserving effect via osteogenic and anti-resorptive mechanisms resulting in the maintenance of bone mass, microarchitecture, material, and strength., Competing Interests: Authors AG and LH were employed by Pharmanza Herbal Pvt. Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kulkarni, Sharma, Porwal, Rajput, Sadhukhan, Singh, Singh, Baranwal, Kumar, Girme, Pandey, Singh, Sashidhara, Kumar, Hingorani and Chattopadhyay.)

A new multianalytical methodology based on gas chromatography (GC) and liquid chromatography (LC) coupled to mass spectrometry (MS) has been proposed to evaluate frauds affecting the composition of Coleus forskohlii root supplements (FKS). After optimization and validation of chromatographic methods, 24 FKS were analyzed. Forskolin, their main bioactive component, was only found in 50% of the FKS evaluated (in the 0.032-17.1% range), with 27% of these supplements showing concentrations of this bioactive lower than those declared in their labels. Application of this methodology also proved to be successful for the detection of frauds regarding the replacement of C. forskohlii by other vegetable sources (green tea, soy leaves and a plant of the Berberidaceae family) in 17% of supplements analyzed. A study on stability of forskolin under accelerated conditions allowed to rule out its degradation as responsible for the lack of this bioactive or other natural constituents in 25% of FKS evaluated. It can be concluded that the multianalytical methodology here developed is an advantageous alternative to address the wide diversity of frauds affecting these supplements., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

The present study was designed to determine protective effects of Coleus forskohlii hydroalcoholic leaf-extract along with its fractions against fructose-induced cataract rat model. The Coleus forskolii leaf extract was subjected to silica gel column chromatography and fractions were collected. A major high yielding fraction of the leaf extract, designated as fraction B6 was pharmacologically evaluated in Sprague Dawley albino rats at three doses 0.1, 1 and 10 mg/kg respectively. Compound B2; isolated from B6 fraction, identified as 'gallic acid' was also pharmacologically evaluated at three different doses. Cataract was induced by concurrent administration of fructose solution (10% w/v, per oral, dissolved in drinking water) for eight consecutive weeks. Mean arterial pressure, blood glucose level and lenticular opacity were determined. At the end of eight weeks, C. forskohlii leaf extract fraction and gallic acid reduced mean arterial pressure and glucose level in a dose dependent manner. In addition, C. forskohlii led to significant restoration of lens antioxidants enzyme level and reduced cataract formation in rats. These results showed the concentration dependent protective effect by C. forskohlii leaf extract against cataract formation due to restoration of oxidative stress markers.

Forskolin (1) is a diterpene found in the Coleus forskohlii plant that has been examined for its medical properties resulting from adenylyl cyclase activation. This article describes a straightforward purification method of 1 from commercially available weight loss capsules. In addition, there has been some ambiguity with respect to the use of the name 'forskolin' to describe 1 and related diterpenes, which this report serves to eliminate. Herein we detail the complete spectroscopic characterization of purified 1 as well as its single crystal X-ray structure., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Obesity is related to energy imbalance and energy metabolism. In this study, we investigated the anti-obesity effects of Garcinia indica extract (GIE), Coleus forskohlii extract (CFE), and the combinations of these two extracts in a 3T3-L1 cells and high-fat diet (HFD)-induced obese mice. In vitro, GIE showed better effect on TG content than CFE, CFE showed better effect on glycerol released than GIE, and the combinations of GIE and CFE showed both effects compared with GIE and CFE alone. In vivo, GIE, LMIX (0.005% GIE + 0.025% CFE), and HMIX (0.01% GIE + 0.025% CFE) down-regulated adipogenesis-related transcription factors PPARγ and C/EBPα protein expression, CFE promoted lipolysis by up-regulated p-HSL and p-PKA protein expression, and four supplementations promoted fatty acid β-oxidation by up-regulating CPT-1A and PPARα protein expression to decrease lipid accumulation in adipose tissue. Moreover, we found that CFE, LMIX and HMIX, except GIE exert increasing the abundance of Bacteroides caccae compared with HFD group. Overall, GIE, CFE, and the combinations of GIE and CFE were able to decrease body weight and adipocyte size by promoting fatty acid β-oxidation and modulating gut microbiota in HFD-induced obese mice., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

To understand the compatibility of three native endophytic fungi Phialemoniopsis cornearis (SF1), Macrophomina pseudophaseolina (SF2) and Fusarium redolens (RF1) with Trichoderma viride (TV1) on Coleus forskohlii in enhancing plant growth and forskolin content, field experiments were conducted. Co-inoculation of RF1+TV1 showed significant improvement in plant growth (52%), root biomass (67%), and in-planta forskolin content (94%), followed by treatment with SF2+TV1 and SF1+TV1. qRT-PCR was carried out to quantify expression of five key forskolin biosynthetic pathway genes (CfTPS2, CfTPS3, CfTPS4, CfCYP76AH15, and CfACT1-8) in RF1+TV1 treated C. forskohlii plants. Elevated expression of CfTPS2, CfTPS4, CfCYP76AH15 and CfACT1-8 genes was observed with RF1+TV1 combination as compared to uninoculated C. forskohlii plants. Besides, RF1+TV1 treatment considerably reduced the severity of nematode infection of C. forskohlii plants under field conditions. Thus, congruent properties of F. redolens (RF1) were witnessed with co-inoculation of T. viride (TV1) under field conditions which resulted in enhanced forskolin content, root biomass, and reduced nematode infections in C. forskohlii. Overall, this approach could be an economical and sustainable step towards cultivation of commercially important medicinal plants., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Coleus forskohlii is an herb, well-known for its medicinal compound forskolin present in its roots, with wide range of pharmaceutical applications. Here, we report, for the first time, the role of plant-probiotic bacterial endophytes of C. forskohlii, CFLB1 and CFRB1, isolated from leaf and root, which regulate plant growth and in plant forskolin content. Native bacterial endophyte, CFRB1 (Alcaligenes faecalis), significantly modulates primary plant productivity and forskolin content under pot and field conditions. Under field conditions, CFRB1 endophyte application significantly enhanced photosynthetic pigments and reduced the severity of root-knot and root rot diseases. Expression analyses of functional genes involved in the forskolin biosynthesis in C. forskohlii plants treated with CFRB1 endophyte under field conditions revealed differential upregulation of four C. forskohlii diterpene synthases (CfTPSs), CfTPS1, CfTPS2, CfTPS3 and CfTPS4, along with cytochrome P450 (CfCYP76AH15) and acyltransferase (CfACT1-8) genes. CFRB1 treatment reduced the severity of nematode infection and root rot in C. forskohlii plants by 81 and 78%, respectively. Overall, we demonstrate that cross-talk of plant-endophyte interaction in C. forskohlii is beneficial, leading to enhanced forskolin content through modulation of forskolin biosynthetic pathway genes along with increased plant yield and reduced disease incidence. Thus, endophytic isolate, A. faecalis (CFRB1), could be deployed as a novel bio-stimulant for enhancing in planta forskolin content during cultivation of C. forskohlii.

Obesity is one of the main causes of non-alcoholic steatohepatitis (NASH), which is associated with impaired liver functions including drug metabolism. Coleus forskohlii extract (CFE) is a popular ingredient of weight loss dietary supplements in Japan. In this study, we examined the effect of CFE on the treatment of NASH. C57BL/6 mice (male, 10-wk-old) were fed a NASH diet (high-fat, low-methionine, and choline-deficient diet) for 12 wk to establish NASH. Then, we examined the effect of 0.5% (w/w) CFE in diet during diet-treatment (change to control diet) and/or treadmill-exercise (45 min at 20 m/min, 5 d/wk) to improve NASH for 3 wk. After experimental period, lipids profiles and liver functional markers in the blood, and hepatic lipid content and major CYP subtype mRNA expression and activity in liver were measured. Diet-treatment, but not exercise decreased liver weight and hepatic lipid contents in NASH induced mice. CFE attenuated the effects of diet-treatment which reduced liver weight, even though body weight and adipose tissue weight were reduced. Further, CFE significantly increased liver microsomal CYP1A1, CYP1A2, CYP2C, and CYP3A activities in each condition, and CYP inductions were greater in diet-treatment group compared to those in exercise group. These results suggest that taking CFE should be avoided during diet-treatment of NASH, especially in patients under medication.

Coleus forskohlii is a perennial medicinal shrub cultivated mainly for its forskolin content. The plant has been used since ancient times in ayurvedic traditional medicines for the treatment of hypertension, glaucoma, asthma, congestive heart failures, obesity, and cancer. Use of endophytic microorganisms presents a special interest for the development of value-added bioactive compounds through agriculture. Limited investigations have been undertaken on in planta enhancement of forskolin content using endophytic fungus in sustainable agriculture. Here we report specific roles of three fungal endophytes, Fusarium redolens (RF1), Phialemoniopsis cornearis (SF1), and Macrophomina pseudophaseolina (SF2), functionally acting as plant probiotic fungus, regulating secondary metabolite (forskolin) biosynthesis in C. forskohlii. The root endophyte, RF1, and shoot endophytes, SF1 and SF2, were found to enhance forskolin content by 52 to 88% in pot and 60 to 84% in field experiments as compared to uninoculated control plants. The three endophytes also enhanced total biomass owing to plant growth promoting properties. The expression of diterpene synthases (CfTPSs) like CfTPS1, CfTPS2, CfTPS3, and CfTPS4 were significantly upregulated in endophyte-treated C. forskohlii plants. Elevated expression of key diterpene synthases (CfTPS2) in the forskolin biosynthesis pathway, exclusively present in the root cork of C. forskohlii, was observed following SF2 endophyte treatment. Furthermore, endophyte treatments conferred a variety of antagonistic activity against nematode galls (80%) and plant pathogens like Fusarium oxysporum, Colletotricum gloeosporioides, and Sclerotium rolfsii. RF1 and SF1 fungal endophytes showed positive for IAA production; however, SF1 also indicated phosphate solubilization activity. Overall, the qualitative and quantitative improvement of in planta forskolin enhancement represents an area of high commercial interest, and hence, our work focused on novel insights for the application of three fungal endophytes for in planta enhancement of forskolin content for C. forskohlii cultivation by a sustainable approach.

Deployment of plant endophytes at field level is reported to make an impact on agricultural crop productivity; development and deployment of suitable crop specific plant probiotics in a suitable delivery matrix is a value-added task. In our study, we attempted to develop bioformulations of native, fungal endophytes of Coleus forskohlii to improve plant yield using two different carrier-based materials (talc and wheat bran). Initially, fungal endophytes (RF1, SF1, and SF2) were grown on sterilized wheat bran under solid state condition and their growth kinetics and pattern were analyzed by ergosterol content and scanning electron microscope, respectively. 10-day-grown fungal endophytic cultures were used for the development of two types of formulations (wheat bran and talc-based formulations) and tested for their efficacy on host plant, C. forskohlii under field conditions. Interestingly, application of wheat bran-based endophytic formulations significantly (p < 0.01) enhanced plant height (12-29%), number of branches (51-63%), root biomass (26-33%), photosynthetic pigments (32-101%), and forskolin content (35-56%) compared to talc-based formulations under field conditions. Shelf life of endophytes (RF1, SF1, and SF2) in both formulations revealed spore viability in wheat bran-based formulations for 6 months storage period as compared to talc-based formulations. Overall, the present investigation envisages developing plant probiotic bioformulations of functional endophytes of C. forskohlii to enhance root biomass and in planta forskolin content., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Coleus forskohlii extract (CFE), a popular weight-loss herbal product, induces hepatic cytochrome P450 (CYP) and fatty liver in mice; however, its main bioactive ingredient, forskolin, does not show such effects. To ensure the safety of CFE as a dietary supplement, identification of the compounds implicated in the induction of hepatic CYP and fatty liver is required. In this study, we separated a crude CFE extract into 5 fractions (Fr.) by column chromatography and administered the fractions to mice for one week to assess their ability to induce CYP and fatty liver. CYP induction was detected for all fractions, indicating that many compounds may be involved in CYP induction, while fatty liver was only detected for Fr. 2. Further isolation and purification of Fr. 2 by column chromatography identified 14-deoxycoleon U as a major compound and crocetin dialdehyde as a pigment compound. An in vivo mouse study revealed that crocetin dialdehyde had no effect on the liver and, as 14-deoxycoleon U was the major compound in Fr. 2, it is likely that the active compound inducing fatty liver in CFE is 14-deoxycoleon U. These findings will facilitate the preparation of standardized safe CFE ingredients for dietary supplements.

In modern era, the great interest and demand among chemists and researchers for metal nanoparticles is increasing in the application of biomedical fields, textiles, cosmetics and various sectors. Consequently, the present study reports an eco-friendly, cost-effective, rapid and easy method to produce environment-friendly metal nanoparticles to prevent exhaustion of metal resources. In this context, gold and silver metal nanoparticles were green synthesized using the Root Extract of Coleous forskohlii (RECo) as capping and reducing agent. The synthesized gold (GNPs) and silver nanoparticles (SNPs) were characterized using UV-Visible spectrophotometer, High-resolution transmission electron microscopy (HR-TEM), Particle size analysis (PSA), Fourier-transform infrared spectroscopy (FT-IR) and X-Ray Diffractometer (XRD). Their clinical importance was analysed using anti-oxidant assay (DPPH - 2,2-diphenyl-1-picrylhydrazyl and Phosphomolybdenum PMA) and cytotoxicity (MTT assay) against HEPG2 (liver cancer cell lines). Further, the antimicrobial activity against two microorganisms were tested using disc diffusion method against Proteus vulgaris pathogen and Micrococcus luteus pathogen. RECo-GNPs and SNPs were found to be stable in aqueous medium for a longer time and exhibited favorable anti-oxidant, anti-bacterial and anti-cancer activity. The phytoconstituents present in the root extract of Coleous forskohlii was elucidated using GC-MS analysis., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Ultraviolet (UV)-B radiation and the growth hormone indole-3-acetic acid (IAA) have been known to cause various changes in plants at morphological and physiological levels as individual entities, but their interactive effects on the overall plant performance remain practically unknown. The present study was conducted under near-natural field conditions to evaluate the effects of supplemental (s)-UV-B (ambient+3.6kJm -2 day -1 ) treatment alone, and in combination with two doses of IAA (200ppm and 400ppm) exogenously applied as foliar spray on various growth-, morphological-, physiological-, and biochemical parameters of an indigenous medicinal plant, Coleus forskohlii. Under s-UV-B, the plant growth and morphology were adversely affected (along with reductions in protein- and chlorophyll contents) with concomitant increase in secondary metabolites (as substantiated by an increase in the activities of various enzymes of the phenylpropanoid pathway) and cumulative antioxidative potential (CAP), suggesting the plant's capability of adaptive resilience against UV-B. The essential oil content of the plant was, however, compromised reducing its pharmaceutical value. IAA application at both doses led to a reversal in the effects caused by s-UV-B radiation alone; both the plant growth as well as the essential oil content improved, especially at the higher IAA dose, suggesting its ameliorative role against UV-B induced oxidative stress, and also in improving the plant's medicinal value., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Forskolin is a unique structurally complex labdane-type diterpenoid used in the treatment of glaucoma and heart failure based on its activity as a cyclic AMP booster. Commercial production of forskolin relies exclusively on extraction from its only known natural source, the plant Coleus forskohlii , in which forskolin accumulates in the root cork. Here, we report the discovery of five cytochrome P450s and two acetyltransferases which catalyze a cascade of reactions converting the forskolin precursor 13 R -manoyl oxide into forskolin and a diverse array of additional labdane-type diterpenoids. A minimal set of three P450s in combination with a single acetyl transferase was identified that catalyzes the conversion of 13 R -manoyl oxide into forskolin as demonstrated by transient expression in Nicotiana benthamiana . The entire pathway for forskolin production from glucose encompassing expression of nine genes was stably integrated into Saccharomyces cerevisiae and afforded forskolin titers of 40 mg/L.

The effects of supplemental ultraviolet-B (s-UV-B; 3.6 kJ m(-2) day(-1) above ambient) radiation were investigated on plant metabolite profile, essential oil content and composition, and free radical scavenging capacities of methanolic extracts of Coleus forskohlii (an indigenous medicinal plant) grown under field conditions. Essential oil was isolated using hydrodistillation technique while alterations in metabolite profile and oil composition were determined via gas chromatography-mass spectroscopy (GC-MS). Leaf and root methanolic extracts were investigated via various in vitro assays for their DPPH radical-, superoxide radical-, hydrogen peroxide-, hydroxyl radical-, and nitric oxide radical scavenging activities, ferrous ion chelating activity, and reducing power. Phytochemical analysis revealed the presence of alkaloids, anthocyanins, coumarins, flavonoids, glycosides, phenols, saponins, steroids, tannins, and terpenoids. Oil content was found to be reduced (by ∼7 %) in supplemental UV-B (s-UV-B) treated plants; the composition of the plant extracts as well as essential oil was also considerably altered. Methanolic extracts from treated plant organs showed more potency as free radical scavengers (their EC50 values being lower than their respective controls). Anomalies were observed in Fe(2+) chelating activity for both leaves and roots. The present study concludes that s-UV-B adversely affects oil content in C. forskohlii and also alters the composition and contents of metabolites in both plant extracts and oil. The results also denote that s-UV-B treated plant organs might be more effective in safeguarding against oxidative stress, though further studies are required to authenticate these findings.

Supplementary ultraviolet-B (ambient+3.6  kJ m(-2) day(-1)) induced changes on morphological, physiological, and biochemical characteristics (specifically the defence strategies: UV-B protective compounds and antioxidants) of Coleus forskohlii were investigated under field conditions at 30, 60, and 90 days after transplantation. Levels of secondary metabolites increased under s-UV-B stress; flavonoids and phenolics (primary UV-B screening agents) were recorded to be higher in leaves which are directly exposed to s-UV-B. This was also verified by enhanced activities of phenylpropanoid pathway enzymes: phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), 4-coumarate-CoA ligase (4CL), chalcone-flavanone isomerase (CHI), and dihydroflavonol reductase (DFR). Antioxidants, both enzymatic (ascorbate peroxidase, catalase, glutathione reductase, peroxidase, polyphenol oxidase, and superoxide dismutase) and non-enzymatic (ascorbic acid and α-tocopherol) also increased in the treated organs of the test plant, higher contents being recorded in roots except for ascorbic acid. On the contrary, protein and chlorophyll content (directly implicated in regulating plant growth and development) declined under s-UV-B. These alterations in plant biochemistry led the plant to compromise on its photosynthate allocation towards growth and biomass production as evidenced by a reduction in its height and biomass. The study concludes that s-UV-B is a potent stimulating factor in increasing the concentrations of defense compounds and antioxidants in C. forskohlii to optimize its performance under stress., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Phytogeographical variation has an impact on up/down regulation of secondary metabolites in medicinal plants. In the same context, present study was planned to evaluate the variation of forskolin content in Coleus forskohlii from Vidarbha region (Maharashtra), India having different topographical conditions. The chemotypic variation was further correlated with existing soil profile. The data revealed the similarity in morphological, macroscopic and microscopic characters of collected germplasms but there is significant ( p < 0.05) variation in the content of chemical marker, forskolin. Physicochemical and phytochemical parameters are within the limits of API and serve as standard for commercial utility of samples. NBC-29 (Narkhed) and NBC-31 (Katol) are the first two high forskolin yielding samples, which are clustered together on the basis of forskolin content with similar soil profiles. Furthermore our study demonstrated that there is significant variation in available NPK and micronutrient content within the soil samples and may be reasoned for existing chemotypic variability in samples. Among the micronutrients, manganese and copper exhibit the positive correlation with forskolin. Thus, elite chemotype of C. forskohlii were identified among the samples collected from Vidarbha region and express the relevance of phyto-geographical conditions on the quantity of industrially viable metabolites, forskolin. This aids in site specific exploration of high metabolite yielding accession/samples to meet out the commercial demands and, supply and to promote the agriculture practices of this industrial crop for societal upliftment in area having similar phytogeographical locations. [ABSTRACT FROM AUTHOR]

Abstract: Significant attention has been devoted to studying hairy root cultures as a promising strategy for production of various valuable secondary metabolites. These offer many advantages, such as high growth rate, genetic stability and being hormone-free. In this study, a detailed phytochemical investigation of the secondary metabolites of Coleus forskohlii hairy root cultures was undertaken and which resulted in the isolation of 22 compounds, including four forskolin derivatives and a monoterpene. Their structures were elucidated by extensive spectroscopic analyses. These compounds could be classified into four groups viz.: labdane-type diterpenes, monoterpenes, triterpenes and phenylpropanoid dimers. Apart from one compound, all labdane type diterpenes are oxygenated at C-11 as in forskolin and a scheme showing their biosynthetic relationships is proposed. [Copyright &y& Elsevier]

Plectranthus barbatus (syn . Coleus forskohlii) is the only known source of forskolin, a compound with a wide range of pharmacological activities. Here, an efficient protocol for adventitious root regeneration from leaf explants of P. barbatus was developed. Different concentrations of plant growth regulators individually and in combination were used to induce roots in vitro. Morphogenic responses and forskolin production varied depending on the concentrations of plant growth regulators added to the medium. Lower concentrations of auxins trigger callus proliferation while higher concentrations induced adventitious root regeneration. Of all the auxins, 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 2 (2,4,5-trichlorophenoxy) propionic acid (2,4,5-TP), and 4-amino-3,5,6-trichloropicolinic acid (picloram) induced callus, whereas α-naphthaleneacetic acid (NAA), indole-3-acetic acid, and indole-3-butyric acid induced rhizogenesis. Use of picloram at 1.0 and 0.5 mg l resulted in the formation of friable callus, and when combined with 0.5 mg l 6-benzylamino purine (BA), rhizogenic callus was produced. The cytokinins BA and kinetin produced a mixed response of multiple shoot regeneration, callus proliferation, and rhizogenesis. The maximum forskolin content of 1,178 mg kg dry weight was found in root cultures initiated on Gamborg's B medium supplemented with 0.5 mg l NAA. The biosynthesis of forskolin was differentiation dependent, and rhizogenic cultures exhibited the maximum biosynthetic potential for forskolin. [ABSTRACT FROM AUTHOR]