Steroidal alkaloid saponins and steroidal saponins from Solanum surattense

Search for new steroidal glycosides with anti-cancer potential from natural resources

Chemical investigations of higher plants, with particular attention paid to their steroidal glycosides, present a promising approach for generating anti-cancer agents from natural products. We conducted a systematic phytochemical investigation of nine higher plants-whole plants and rhizomes of Convallaria majalis, whole plants of Agave utahensis, roots of Adonis amurensis, seeds of Adonis aestivalis, bulbs of Bessera elegans, bulbs of Fritillaria meleagris, seeds of Digitalis purpurea, underground parts of Yucca glauca, and bulbs of Lilium pumilum-which led to the discovery of novel steroidal glycosides. The structures of these new constituents were determined based on spectroscopic data and chemical transformations. The identification of the monosaccharides including their absolute configurations was carried out by direct HPLC analysis of their hydrolysates using an optical rotation detector. Cytotoxicity of the isolated steroidal glycosides was evaluated against various tumor cells (A549, ACHN, HepG-2, HL-60, HSC-2, HSC-3, HSC-4, HSG, and SBC-3) and normal cells (Fa2 N-4, HK-2, and TIG-3 cells). Certain steroidal glycosides exhibit selective cytotoxicity and synergistic effects, making them potential lead compounds for use as anti-cancer agents. We document the isolation of 139 steroidal glycosides from higher plants and assessment their cytotoxic activities.

Ethnomedicinal Usage, Phytochemistry and Pharmacological Potential of Solanum surattense Burm. f

Solanum surattense Burm. f. is a significant member of the Solanaceae family, and the Solanum genus is renowned for its traditional medicinal uses and bioactive potential. This systematic review adheres to PRISMA methodology, analyzing scientific publications between 1753 and 2023 from B-on, Google Scholar, PubMed, Science Direct, and Web of Science, aiming to provide comprehensive and updated information on the distribution, ethnomedicinal uses, chemical constituents, and pharmacological activities of S. surattense, highlighting its potential as a source of herbal drugs. Ethnomedicinally, this species is important to treat skin diseases, piles complications, and toothache. The fruit was found to be the most used part of this plant (25%), together with the whole plant (22%) used to treat different ailments, and its decoction was found to be the most preferable mode of herbal drug preparation. A total of 338 metabolites of various chemical classes were isolated from S. surattense, including 137 (40.53%) terpenoids, 56 (16.56%) phenol derivatives, and 52 (15.38%) lipids. Mixtures of different parts of this plant in water-ethanol have shown in vitro and/or in vivo antioxidant, anti-inflammatory, antimicrobial, anti-tumoral, hepatoprotective, and larvicidal activities. Among the metabolites, 51 were identified and biologically tested, presenting antioxidant, anti-inflammatory, and antitumoral as the most reported activities. Clinical trials in humans made with the whole plant extract showed its efficacy as an anti-asthmatic agent. Mostly steroidal alkaloids and triterpenoids, such as solamargine, solanidine, solasodine, solasonine, tomatidine, xanthosaponin A-B, dioscin, lupeol, and stigmasterol are biologically the most active metabolites with high potency that reflects the new and high potential of this species as a novel source of herbal medicines. More experimental studies and a deeper understanding of this plant must be conducted to ensure its use as a source of raw materials for pharmaceutical use.

New Solasodine-Type Glycoalkaloids Isolated from Solanum nigrum and Their Cytotoxic Activity

Three undescribed solalodine-type glycoalkaloids, named solanigrinoside A-C (1-3), and six known compounds (4-9) were isolated from the whole plants of Solanum nigrum. Their structures were elucidated based on analysis of HR-ESI-MS, 1D- and 2D-NMR spectral data, and comparison with those reported in literatures. The solanigrinoside A-C (1-3), solasodine (4), and 3-acetoxysolasodine (5) exhibited cytotoxic effects against LU-1, Hep-G2, and MCF-7 cells with IC50 values in range from 4.6 μM to 56.2 μM. Compound 2 showed the significant cytotoxic activity with corresponding IC50 values of 5.7 μM, 7.9 μM, and 4.6 μM, respectively.

Fourteen undescribed steroidal saponins from Solanum capsicoides leaves and their neuroprotective effects

A total of 14 previously undescribed steroidal saponins named capsicsaponins A-N were isolated from the leaves of Solanum capsicoides, encompassing various types, including cholesterol derivatives and pseudospirostanol saponins. The structures of all compounds were determined through comprehensive analysis of spectroscopic data (1D NMR and 2D NMR), along with physicochemical analysis methods (acid hydrolysis, OR, and UV). Moreover, in the H2O2-induced pheochromocytoma cell line model, compounds 1-14 were screened for their neuroprotective effects on cells. The bioassay results demonstrated compounds 8-14 were able to revive cell viability compared to the positive control edaravone. The damage neuroprotection of the most active compound was further explored.

Inhibiting Angiogenesis by Anti-Cancer Saponins: From Phytochemistry to Cellular Signaling Pathways

Saponins are one of the broadest classes of high-molecular-weight natural compounds, consisting mainly of a non-polar moiety with 27 to 30 carbons and a polar moiety containing sugars attached to the sapogenin structure. Saponins are found in more than 100 plant families as well as found in marine organisms. Saponins have several therapeutic effects, including their administration in the treatment of various cancers. These compounds also reveal noteworthy anti-angiogenesis effects as one of the critical strategies for inhibiting cancer growth and metastasis. In this study, a comprehensive review is performed on electronic databases, including PubMed, Scopus, ScienceDirect, and ProQuest. Accordingly, the structural characteristics of triterpenoid/steroid saponins and their anti-cancer effects were highlighted, focusing on their anti-angiogenic effects and related mechanisms. Consequently, the anti-angiogenic effects of saponins, inhibiting the expression of genes related to vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1-α (HIF-1α) are two main anti-angiogenic mechanisms of triterpenoid and steroidal saponins. The inhibition of inflammatory signaling pathways that stimulate angiogenesis, such as pro-inflammatory cytokines, mitogen-activated protein kinase (MAPKs), and phosphoinositide 3-kinases/protein kinase B (PI3K/Akt), are other anti-angiogenic mechanisms of saponins. Furthermore, the anti-angiogenic and anti-cancer activity of saponins was closely related to the binding site of the sugar moiety, the type and number of their monosaccharide units, as well as the presence of some functional groups in their aglycone structure. Therefore, saponins are suitable candidates for cancer treatment by inhibiting angiogenesis, for which extensive pre-clinical and comprehensive clinical trial studies are recommended.

Phenylpropanoids from Solanum capsicoides and their anti-inflammatory activity

Two new phenylpropanoids, 4-O-(1''-O-cis-caffeoyl)-β-glucopyran osyl-1-allyl-3-methoxy-benzene (1), 4'-O-(1''-O-cis-caffeoyl)-β-glucopyranosyl-hydroxymegastigm-4-en-3-one (2), together with nine known compounds were obtained from the leaves of Solanum capsicoides. Their structures were elucidated based on spectroscopic methods, and comparing spectral data with those in literature. Meanwhile, their anti-inflammatory activities were evaluated on (LPS)-induced RAW 246.7 cells, and 1, 9, and 10 showed better inhibitory effects with IC₅₀ values of 17.19 ± 1.12, 18.15 ± 0.47, and 19.8 ± 0.95 μM, respectively.

Inositol Derivatives with Anti-Inflammatory Activity from Leaves of Solanum capsicoides Allioni

Eight new inositol derivatives, solsurinositols A-H (1-8), were isolated from the 70% EtOH extract of the leaves of Solanum capsicoides Allioni. Careful isolation by silica gel column chromatography followed by preparative high-performance liquid chromatography (HPLC) allowed us to obtain analytically pure compounds 1-8. They shared the same relative stereochemistry on the ring but have different acyl groups attached to various hydroxyl groups. This was the first time that inositol derivatives have been isolated from this plant. The chemical structures of compounds 1-8 were characterized by extensive 1D nuclear magnetic resonance (NMR) and 2D NMR and mass analyses. Meanwhile, the in vitro anti-inflammatory activity of all compounds was determined using lipopolysaccharide (LPS)-induced BV2 microglia, and among the isolates, compounds 5 (IC₅₀ = 11.21 ± 0.14 µM) and 7 (IC₅₀ = 14.5 ± 1.22 µM) were shown to have potential anti-inflammatory activity.

Eight undescribed steroidal saponins including an unprecedented 16, 26-epoxy-furostanol saponin from Solanum xanthocarpum and their cytotoxic activities

Eight undescribed steroidal saponins named solasaponins A-H were isolated from the fruits of Solanum xanthocarpum, including an unusual 16,26-epoxy-furostanol saponin, two furostanol saponins, three isospirostanol saponins, two pseudo-spirostanol saponins. The structures of all compounds were elucidated by extensive spectroscopic data analyses (1D, 2D NMR, and HRESIMS) combined with physico-chemical analysis methods (acid hydrolysis, optical rotation, and IR). The cytotoxicities of all compounds in vitro against two human cancer cell lines (A-549 and HepG2) were evaluated by CCK-8 assay.

Chemistry and bioactivities of natural steroidal alkaloids

Steroidal alkaloids possess the basic steroidal skeleton with a nitrogen atom in rings or side chains incorporated as an integral part of the molecule. They have demonstrated a wide range of biological activities, and some of them have even been developed as therapeutic drugs, such as abiraterone acetate (Zytiga^®), a blockbuster drug, which has been used for the treatment of prostate cancer. Structurally diverse natural steroidal alkaloids present a wide spectrum of biological activities, which are attractive for natural product chemistry and medicinal chemistry communities. This review comprehensively covers the structural classification, isolation and various biological activities of 697 natural steroidal alkaloids discovered from 1926 to October 2021, with 363 references being cited.

The anti-hepatitis B virus and anti-hepatotoxic efficacies of solanopubamine, a rare alkaloid from Solanum schimperianum

Chronic liver disease caused by hepatitis B virus (HBV) remains an important health issue. Though there are effective HBV-polymerase inhibitors (e.g., lamivudine), their prolonged use leads to emergence of drug-resistant (polymerase mutant) strains. Several herbal formulations and phytochemicals have been therefore, reported as potential anti-HBV agents with no sign of resistance in experimental and clinical settings. In this study, we assessed the anti-HBV as well as hepatoprotective salutations of solanopubamine, a rare alkaloid isolated from S. schimperianum. In cultured HepG2.2.15 cells, solanopubamine showed marked anti-HBV activity in a time and dose-dependent manner. Solanopubamine (30 μM) efficiently inhibited HBsAg and HBeAg expressions by 66.5%, 70.5%, respectively as compared to 82.5% and 86.5% respective inhibition by lamivudine (2 μM) at day 5. Molecular docking analyses of solanopubamine revealed formations of stable complexes with lamivudine-sensitive as well as lamivudine-resistant polymerase through interactions of catalytic ‘YMDD/YIDD’ motif residues. Moreover, solanopubamine attenuated DCFH-induced oxidative and apoptotic damage and restored HepG2 cell viability by 28.5%, and downregulated caspase-3/7 activations by 33%. Further docking analyses of solanopubamine showed formation of stable complexes with caspase-3/7. Taken together, our data demonstrates promising anti-HBV and anti-hepatotoxic therapeutic potential of solanopubamine, and warrants further molecular and pharmacological studies.

Solanum Fruits: Phytochemicals, Bioaccessibility and Bioavailability, and Their Relationship With Their Health-Promoting Effects

The Solanum genus is the largest in the Solanaceae family containing around 2,000 species. There is a great number of edibles obtained from this genus, and globally, the most common are tomato (S. lycopersicum), potato (S. tuberosum), and eggplant (S. melongena). Other fruits are common in specific regions and countries, for instance, S. nigrum, S. torvum, S. betaceum, and S. stramonifolium. Various reports have shown that flavonoids, phenolic acids, alkaloids, saponins, and other molecules can be found in these plants. These molecules are associated with various health-promoting properties against many non-communicable diseases, the main causes of death globally. Nonetheless, the transformations of the structure of antioxidants caused by cooking methods and gastrointestinal digestion impact their potential benefits and must be considered. This review provides information about antioxidant compounds, their bioaccessibility and bioavailability, and their health-promoting effects. Bioaccessibility and bioavailability studies must be considered when evaluating the bioactive properties of health-promoting molecules like those from the Solanum genus.

Chemical synthesis of saponins: An update

Saponins, as secondary metabolites in terrestrial plants and marine invertebrate, constitute one of the largest families of natural products. The long history of folk medicinal applications of saponins makes them attractive candidates for innovative drug design and development. Chemical synthesis has become a practical alternative to the availability of the natural saponins and their modified analogs, so as to facilitate SAR studies and the discovery of optimal structures for clinical applications. The recent achievements in the synthesis of these complex saponins reflect the advancements of both steroid/triterpene chemistry and carbohydrate chemistry. This chapter provides an updated review on the chemical synthesis of natural saponins, covering the literature from 2014 to 2020.

Solanum steroidal glycoalkaloids: structural diversity, biological activities, and biosynthesis

Chemical structures of typical Solanum steroidal glycoalkaloids from eggplant, tomato, and potato.

Stereospecific synthesis and rearrangement of 22S-23-acetylsapogenins

The BF₃·Et₂O-catalysed acetolysis of steroid sapogenins diosgenin, sarsasapogenin and tigogenin in dichloromethane as the solvent instead of acetic anhydride afforded (20S)- and (20R)-22,26-epoxycholestanes (compounds 1 and 2). 22S-23-Acetylsapogenins (compounds 4) were synthesized stereospecifically from 20R-22,26-epoxycholestanes (compounds 2) in good yield. The rearrangement of 22S-23-acetylsapogenins (compounds 4) afforded novel disubstituted dihydropyran furostanol frameworks. Exhaustive NMR characterization of the obtained compounds is provided. Additionally, the structures of the critical compounds (6a and 7a) were unequivocallyconfirmed by single crystal X-ray diffraction studies.

Cytotoxic activity of steroidal glycosides from the aerial parts of Solanum torvum collected in Thua Thien Hue, Vietnam

A phytochemical investigation of Solanum torvum led to the isolation of eleven steroidal glycosides, including neochlorogenin 6-O-β-D-quinovopyranoside (1), (22 R,23S,25R)-3β-6α,23-trihydroxy-5α-spirostane 6-O-β-D-xylopyranosyl-(1→3)-β-D-quinovopyranoside (2), neochlorogenin 6-O-α-L-rhamnopyranosyl-(1→3)-β-D-quinovopyranoside (3), solagenin 6-O-α-L-rhamnopyranosyl-(1→3)-β-D-quinovopyranoside (4), paniculonin A (5), paniculonin B (6), 6α-O-[β-D-xylopyranosyl-(1→3)β-D-quinovopyranosyl]-(25S)-5α-spirostan-3β-ol (7), torvoside J (8), torvoside K (9), torvoside L (10) and solagenin 6-O-β-D-quinovopyranoside (11). Their chemical structures were elucidated by 1D-NMR and 2D-NMR data as well as comparison with the data reported in the literature. Moreover, all isolated compounds were evaluated for their cytotoxic activities against SK-LU-1, HepG2, MCF-7 and T24 cancer cell lines. Among them, compounds 1, 3, 7 and 11 exhibited cytotoxicity against all four tested cell lines with IC₅₀ values ranging from 7.89 ± 0.87 to 46.76 ± 3.88 µM.

Hepatoprotective effect of Solanum surattense leaf extract against chemical- induced oxidative and apoptotic injury in rats

Background

Of over 35 Saudi plants traditionally used to treat liver disorders, majority still lack scientific validations. We therefore, evaluated the anti-oxidative, anti-apoptotic and hepatoprotective potential of Solanum surattense leaves total ethanol-extract (SSEE).

Methods

The cytoprotective (4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide/ MTT assay) and anti-apoptotic (caspase-3/7) potential of SSEE (25–200 μg/mL) were assessed in cultured HepG2 cells against dichlorofluorescein (DCFH)-induced toxicity. The hepatoprotective salutation of SSEE (100 and 200 mg/kg.bw/day) in carbon tetrachloride (CCl₄)-intoxicated rats was evaluated by serum biochemistry and histopathology. The anti-oxidative activity of SSEE (31.25–500 μg/mL) was tested by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and linoleic acid bleaching assays. Also, SSEE was subjected to qualitative phytochemical analysis, and standardized by validated high-performance liquid chromatography (HPTLC).

Results

SSEE at doses 50, 100 and 200 μg/mL showed HepG2 cell proliferative and protective potential by about 61.0, 67.2 and 95%, respectively through inhibition of caspase-3/7 against DCFH-toxicity. In CCl₄-injured rats, SSEE (200 mg/kg) significantly (P < 0.001) normalized serum transaminases, alkaline phosphatase, bilirubin, cholesterol, triglycerides, and total protein, including tissue malondialdehyde and nonprotein sulfhydryls levels, supported by the liver histopathology. SSEE further showed strong in vitro anti-oxidative and anti-lipid peroxidative activities, evidenced by the presence of alkaloids, flavonoids, tannins, sterols and saponins. Identification of β-sitosterol (3.46 μg/mg) strongly supported the anti-oxidative and hepatoprotective salutation of SSEE.

Conclusion

Our findings suggest the therapeutic potential of S. surattense against chemical-induced oxidative stress and liver damage. However, isolation of the active principles and elucidation of mechanism of action remain to be addressed.

The Genus Solanum: An Ethnopharmacological, Phytochemical and Biological Properties Review

Over the past 30 years, the genus Solanum has received considerable attention in chemical and biological studies. Solanum is the largest genus in the family Solanaceae, comprising of about 2000 species distributed in the subtropical and tropical regions of Africa, Australia, and parts of Asia, e.g., China, India and Japan. Many of them are economically significant species. Previous phytochemical investigations on Solanum species led to the identification of steroidal saponins, steroidal alkaloids, terpenes, flavonoids, lignans, sterols, phenolic comopunds, coumarins, amongst other compounds. Many species belonging to this genus present huge range of pharmacological activities such as cytotoxicity to different tumors as breast cancer (4T1 and EMT), colorectal cancer (HCT116, HT29, and SW480), and prostate cancer (DU145) cell lines. The biological activities have been attributed to a number of steroidal saponins, steroidal alkaloids and phenols. This review features 65 phytochemically studied species of Solanum between 1990 and 2018, fetched from SciFinder, Pubmed, ScienceDirect, Wikipedia and Baidu, using "Solanum" and the species' names as search terms ("all fields").

Phytoestrogens, phytosteroids and saponins in vegetables: Biosynthesis, functions, health effects and practical applications

Phytoestrogens are non-steroidal secondary metabolites with similarities in structure and biological activities with human estrogens divided into various classes of compounds, including lignans, isoflavones, ellagitannins, coumestans and stilbenes. Similarly, phytosteroids are steroidal compounds of plant origin which have estrogenic effects and can act as agonists, antagonists, or have a mixed agonistic/antagonistic activity to animal steroid receptors. On the other hand, saponins are widely distributed plant glucosides divided into triterpenoid and steroidal saponins that contribute to plant defense mechanism against herbivores. They present a great variation from a structural point of view, including compounds from different classes. In this chapter, the main vegetable sources of these compounds will be presented, while details regarding their biosynthesis and plant functions will be also discussed. Moreover, considering the significant bioactive properties that these compounds exhibit, special focus will be given on their health effects, either beneficial or adverse. The practical applications of these compounds in agriculture and phytomedicine will be also demonstrated, as well as the future prospects for related research.

Two New Steroidal Saponins from Solanum procumbens

Two new steroidal saponins, solaprocumosides A (1) and B (2), and a known compound paniculonin B (3) were isolated from the aerial parts of Solanum procumbens. Their chemical structures were determined by analysis of HR-ESI-MS and NMR spectra. Compound 1 had ketone functional groups at C-16 and C-22 of sterol skeleton which is rarely found in nature. Meanwhile, compound 2 could be form by oxidative breakdown C-20/C-22 bonding of a furostane-type saponin. Compounds 1–3 showed weak cytotoxicity against HepG2 cell line with IC50 values of 55.7 ± 1.5, 48.1 ± 2.2, and 78.3 ± 2.4 μM, respectively.

Recent advances in steroidal saponins biosynthesis and in vitro production

Steroidal saponins exhibited numerous pharmacological activities due to the modification of their backbone by different cytochrome P450s (P450) and UDP glycosyltransferases (UGTs). Plant-derived steroidal saponins are not sufficient for utilizing them for commercial purpose so in vitro production of saponin by tissue culture, root culture, embryo culture, etc, is necessary for its large-scale production. Saponin glycosides are the important class of plant secondary metabolites, which consists of either steroidal or terpenoidal backbone. Due to the existence of a wide range of medicinal properties, saponin glycosides are pharmacologically very important. This review is focused on important medicinal properties of steroidal saponin, its occurrence, and biosynthesis. In addition to this, some recently identified plants containing steroidal saponins in different parts were summarized. The high throughput transcriptome sequencing approach elaborates our understanding related to the secondary metabolic pathway and its regulation even in the absence of adequate genomic information of non-model plants. The aim of this review is to encapsulate the information related to applications of steroidal saponin and its biosynthetic enzymes specially P450s and UGTs that are involved at later stage modifications of saponin backbone. Lastly, we discussed the in vitro production of steroidal saponin as the plant-based production of saponin is time-consuming and yield a limited amount of saponins. A large amount of plant material has been used to increase the production of steroidal saponin by employing in vitro culture technique, which has received a lot of attention in past two decades and provides a way to conserve medicinal plants as well as to escape them for being endangered.

Efficacy of Four Solanum spp. Extracts in an Animal Model of Cutaneous Leishmaniasis

Background: Leishmaniasis is a complex protozoa disease caused by Leishmania genus (Trypanosomatidae family). Currently, there have been renewed interests worldwide in plants as pharmaceutical agents. In this study, the in vivo efficacy of Solanum spp. is assessed in an L. amazonensis BALB/c mice model for experimental cutaneous leishmaniasis. Methods: Animals were infected with 5 × 10⁶ metacyclic promastigotes and 30-day post-infection, a treatment with 30 mg/kg of Solanum extracts or Glucantime^® (GTM) was applied intralesionally every four days to complete 5 doses. Results: Neither death nor loss of weight higher than 10% was observed. All the tested extracts were able to control the infection, compared with the infected and untreated group. Solanum havanense Jacq. extract showed the highest efficacy and was superior (p < 0.05) to GTM. Solanum myriacanthum Dunal., S. nudum Dunal. and S. seaforthianum Andr. extracts demonstrated a similar effect (p > 0.05) to GTM. An increase of IFN-γ (p < 0.05) was displayed only by animals treated with S. nudum compared to the group treated with a vehicle, while no differences (p > 0.05) were observed for IL-12. Conclusions:In vivo effects of Solanum extracts were demonstrated, suggesting that this genus could be further explored as a new antileishmanial alternative.

Chemical constituents of Solanum coagulans and their antimicrobial activities

The present study aimed at determining the chemical constituents of Solanum coagulans and their antimicrobial activities. The compounds were isolated by various chromatographic techniques and their structures were elucidated on the basis of extensive spectroscopic analysis, chemical methods, and comparison with reported spectroscopic data. One new phenolic glycoside, methyl salicylate 2-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1), together with 12 known compounds (2-13), were isolated from the aerial parts of Solanum coagulans. Compound 1 was a new phenolic glycoside, and 2-6 were isolated from Solanum genus for the first time. The antimicrobial activities of the isolated compounds were also evaluated. Compound 7 showed remarkable antifungal activity against T. mentagrophytes, M. gypseum and E. floccosum with MIC values being 3.13, 1.56 and 3.13 μg·mL(-1), respectively.

Steroidal saponins from stems and leaves of Paris polyphylla var. yunnanensis

Phytochemical investigation of the stems and leaves of Paris polyphylla var. yunnanensis led to isolation of 12 steroidal saponins, chonglouosides SL-9-SL-20, which had not been described previously, along with 13 known compounds. Their structures were established on the basis of extensive spectroscopic analysis and chemical methods. Four of the twelve steroidal saponins possessed three steroidal aglycones which have not been reported in nature. Steroidal saponins were also evaluated for their cytotoxicities against two human cancer cell lines (HepG2 and HEK293) and anti-HCV effects. One known steroidal saponin was the most cytotoxic compound overall with IC50 values of 2.9 ± 0.5 μM and 5.0 ± 0.6 μM against HepG2 and HEK293 cell lines, respectively, while none showed anti-HCV activity at a concentration of 20 μM.

Quantitative ethnobotanical survey of medicinal flora thriving in Malakand Pass Hills, Khyber Pakhtunkhwa, Pakistan

STUDY OBJECTIVE

Ethnobotanical knowledge is proving to be invaluable for drug discovery in the wake of effective prospecting from biodiversity. On the other hand, the escalating human pressure is threatening the endogenous flora. Situated at the foothill of the Himalayas, Pakistan boasts of rich floristic distribution. However, many lush yet imperiled regions of this country has never been explored. It inspired us to evaluate and document the taxonomic composition, significance of medicinal plants and associated traditional knowledge in the District of Malakand, Khyber Pakhtunkhwa Province.

MATERIALS AND METHODS

Vegetation growing in Malakand pass hills, Pakistan was studied and data were collected using an open-ended questionnaire, in addition to interviewing the local elderly, knowledgeable persons, and herbal practitioners. Relative Frequency Citation (RFC) and Use Value (UV) of the medicinal plants were calculated and their correlation was determined by Pearson correlation coefficient.

RESULTS

This study encompasses 92 plant species belonging to 56 families thriving in the study area. The information gathered includes ethnobotanical inventory and their pharmacological uses. Quantitative analysis throws light on the consistence of RFC and UV. Asteraceae and Lamiaceae were the most abundant families represented by 6 species each. Shoots were the most used parts (23.6%) and wound healing (7.91%) was the most common therapeutic use.

CONCLUSION

The result obtained from the study implies that local inhabitants rely on these plants for their medicinal requirements. Also, the statistics reveal that, the vegetation can be assessed for potential drug leads. However, urban expansion is threatening the existence of indigenous flora and old generation with ancient herbal wisdom is perishing. So, it appears imperative to preserve the traditional knowledge. This survey is expected to contribute to the discovery of novel bioactive constituents, stimulate conservation efforts of the perturbed flora and promote sustainable exploitation of the medicinal bounty.

Epimerization of C-22 in (25R)- and (25S)-sapogenins

Most of the naturally occurring steroidal sapogenins (C-23 non-substituted frameworks), possess an R configuration at the spiro C-22 center. Their C-22 epimers have become important targets in biological research. This paper describes a procedure to obtain 22S-spirostans from 22R-sapogenins and pseudosapogenin skeletons, without affecting the chirality at either C-25 or C-20. An optimal way to synthesize the pair of C-22 stereoisomers of 23-acetyldiosgenin is also reported. The latter was obtained from a 22,26-epoxycholestane or from 23-acetylfurostene compounds.

Zebrafish bioassay-guided microfractionation identifies anticonvulsant steroid glycosides from the Philippine medicinal plant Solanum torvum

Medicinal plants used for the treatment of epilepsy are potentially a valuable source of novel antiepileptic small molecules. To identify anticonvulsant secondary metabolites, we performed an in vivo, zebrafish-based screen of medicinal plants used in Southeast Asia for the treatment of seizures. Solanum torvum Sw. (Solanaceae) was identified as having significant anticonvulsant activity in zebrafish larvae with seizures induced by the GABAA antagonist pentylenetetrazol (PTZ). This finding correlates well with the ethnomedical use of this plant in the Philippines, where a water decoction of S. torvum leaves is used to treat epileptic seizures. HPLC microfractionation of the bioactive crude extract, in combination with the in vivo zebrafish seizure assay, enabled the rapid localization of several bioactive compounds that were partially identified online by UHPLC-TOF-MS as steroid glycosides. Targeted isolation of the active constituents from the methanolic extract enabled the complete de novo structure identification of the six main bioactive compounds that were also present in the traditional preparation. To partially mimic the in vivo metabolism of these triterpene glycosides, their common aglycone was generated by acid hydrolysis. The isolated molecules exhibited significant anticonvulsant activity in zebrafish seizure assays. These results underscore the potential of zebrafish bioassay-guided microfractionation to rapidly identify novel bioactive small molecules of natural origin.

Anti-Inflammatory Spirostanol and Furostanol Saponins from Solanum macaonense

Eight new spirostanol saponins, macaosides A-H (1-8), and 10 new furostanol saponins, macaosides I-R (9-18), together with six known spirostanol compounds (19-24) were isolated from Solanum macaonense. The structures of the new compounds were determined from their spectroscopic data, and the compounds were tested for in vitro antineutrophilic inflammatory activity. It was found that both immediate inflammation responses including superoxide anion generation and elastase release were significantly inhibited by treatment with compounds 20, 21, and 24 (superoxide anion generation: IC50 7.0, 7.6, 4.0 μM; elastase release: IC50 3.7, 4.4, 1.0 μM, respectively). However, compounds 1 and 4 exhibited effects on the inhibition of elastase release only, with IC50 values of 3.2 and 4.2 μM, respectively, while 19 was active against superoxide anion generation only, with an IC50 value of 6.1 μM. Accordingly, spirostanols may be promising lead compounds for further neutrophilic inflammatory disease studies.

[Sesquiterpenoids from Solanum lyratum]

Ten compounds were isolated and purified by column chromatography over silica gel, preparative TLC, and Sephadex LH-20 from the whole plant of Solanum lyratum. The structures were elucidated on the basis of physico-chemical properties and spectral data as 1beta-hydroxy-1 ,2-dihydro-alpha-santonin (1) , boscialin (2) , blumenol C (3), 3beta-hydroxy-5alpha, 6alpha-epoxy-7-megastigmen-9-one(4), dehydrovomifoliol(5) , blumenol A(6), (1'S,2R,5S, 10R) -2-(1', 2'-dihydroxy-l1'-methylethyl) -6,10-dimethylspiro[4,5] dec-6-en-8-one(7) , (1'R,2R,5S,10R)-2-( 1',2'-dihydroxy-l '-methylethyl) -6,1 l0-dimethylspiro[4,5]dec-6-en-8-one( 8) , 2-(1',2'-dihydroxy-1 '-methylethyl) -6,1 0-dimethyl-9-hydroxyspiro [4,5] dec-6-en-8-one (9) , and grasshopper ketone (10). Compounds 1-10 were isolated from this plant for the first time.

Steroidal glycosides from the bulbs of Bessera elegans and their cytotoxic activities

Examination of the bulbs of Bessera elegans (Liliaceae) led to isolation of nine new and five known steroidal glycosides. The structures of the nine compounds were determined based on the results of spectroscopic analysis, including two-dimensional NMR, and hydrolysis followed by chromatographic and spectroscopic analysis. The isolated compounds and derivatives were evaluated for cytotoxicity against HL-60 human promyelocytic leukemia cells, A549 human lung adenocarcinoma cells, and TIG-3 normal human diploid fibroblasts. One compound, the pseudo-furostanol glycoside, induced apoptosis in HL-60 and A549 cells in a time-dependent manner and cell-cycle arrest at the G0/G1 phase in A549 cells.

Solanidane and iminosolanidane alkaloids from Solanum campaniforme

From the leaves of Solanum campaniforme (Solanaceae), eight solanidane alkaloids were isolated, four of which contain a p-hydroxyphenylethylamine unit. Their structures were established as: 22β,23β-epoxy-solanida-1,4-dien-3-one; 22α,23α-epoxy-10-epi-solanida-1,4,9-trien-3-one; 22α,23α-epoxy-solanida-4-en-3-one; 22β,23β-epoxy-solanida-4-en-3-one; (E)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine; (E)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine; (Z)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine and (Z)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine. All structures were determined using spectroscopic techniques, such as 1D and 2D NMR, and HRESIMS. The cytotoxicity and the antiophidic activities of the alkaloids were evaluated. The alkaloids did not show any cytotoxicity, but inhibited the main toxic actions of Bothrops pauloensis venom.

Anti-neutrophilic inflammatory steroidal glycosides from Solanum torvum

Torvpregnanosides A and B, two pregnane glycosides, and torvoside Q, a 23-keto-spirostanol glycoside, along with twelve known steroidal saponins were isolated from aerial parts of Solanum torvum. Of the latter, four of the 23-hydroxy-spirostanol glycosides, and, a yamogenin glycoside, were in this plant discovered. All structures were identified from spectroscopic data, and all the compounds were tested for in vitro anti-neutrophilic inflammatory activity. Two compounds showed selective inhibition against elastase release and superoxide anion generation, respectively, by human neutrophils with IC50 values of 5.66 and 3.59 μM, while two others inhibited both inflammatory mediators with IC50 values of 0.66-3.49 μM. Structure-activity relationships are discussed.

New sesquiterpenoid derivatives from Solanum lyratum and their cytotoxicities

Three new sesquiterpenoid isopropylidene derivatives, named solajiangxins H and I (1 and 2) and 7-hydroxylsolajiangxin I (3), were isolated from the whole plant of Solanum lyratum. Their structures were elucidated on the basis of integrated spectroscopic techniques, mainly HR-FAB-MS, 1D NMR, and 2D NMR ((1)H-(1)H COSY, HMQC, HMBC, and NOESY). In vitro, compounds 1-3 were found to show significant cytotoxicity against three cancer cells (P-388, HONE-1, and HT-29), and gave IC50 values in the range of 3.2-7.7 μM.

Natural products chemistry research: progress in China in 2011

This article reviews the progress made by Chinese scientists in the field of natural products chemistry in 2011. Selected compounds with unique structural features and/or promising bioactivities are described herein on the basis of structural types.

Steroidal saponins from the fruits of Solanum torvum

Seven steroidal glycosides have been isolated from the fruits of Solanum torvum Swartz. Their structures were established by 2D NMR spectroscopic techniques ((1)H,(1)H-COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry as (25S)-26-(β-D-glucopyranosyloxy)-3-oxo-5α-furost-20(22)-en-6α-yl-O-β-D-xylopyranoside (1), (25S)-26-(β-D-glucopyranosyloxy)-3-oxo-22α-methoxy-5α-furostan-6α-yl-O-β-D-xylopyranoside (2), (25S)-26-(β-D-glucopyranosyloxy)-3β-hydroxy-22α-methoxy-5α-furostan-6α-yl-O-α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranoside (3), (25S)-3β-hydroxy-5α-spirostan-6α-yl-O-β-D-xylopyranoside (4), (25S)-3-oxo-5α-spirostan-6α-yl-O-β-D-xylopyranoside (5), (25S)-3β-hydroxy-5α-spirostan-6α-yl-O-β-D-glucopyranoside (6), (25S)-3β,27-dihydroxy-5α-spirostan-6α-yl-O-β-D-glucopyranoside (7).

Simple and reliable methods for the determination of three steroidal glycosides in the eight species of Solanum by reversed-phase HPLC coupled with diode array detection

INTRODUCTION

Solanum species are important ingredients of many traditional Indian medicines and thus the quality control of their herbal formulations is of paramount concern.

OBJECTIVE

To establish a simple and effective high-performance liquid chromatographic (HPLC) method to evaluate the quality of Solanum species and their herbal formulations.

METHODOLOGY

A rapid, simple, sensitive, robust and reproducible HPLC method was developed for the determination of three steroidal glycosides (SG); indioside D, solamargine and α-solanine in eight species of the genus Solanum. The analytes were separated on a monolithic performance RP-18e column (100 mm × 4.6 mm i.d.) using a gradient elution of acetonitile-water containing 0.1% trifluoroacetic acid (TFA) as the mobile phase with a flow rate 0.4 mL/min and UV detection at λ 210 nm.

RESULTS

The method was linear over the range 3-15 µg/mL (r > 9994). Accuracy, precision and repeatability were all within the required limits. The mean recoveries measured at the three concentrations were higher than 98.8% with RSD < 2% for the targets.

CONCLUSION

The established method is simple and can be used as a tool for quality control of plant material or herbal formulation containing SG.