SC-1, an antimycotic spirostan saponin from Solanum chrysotrichum

Production of antifungal saponins in an airlift bioreactor with a cell line transformed from Solanum chrysotrichum and its activity against strawberry phytopathogens

Biotechnology through plant cell cultures in bioreactors is a tool that allows increasing the production of secondary metabolites of commercial interest. The hydrodynamic characterization, in addition to the transfer (OTR) and uptake (OUR) of oxygen through the dynamic method with different aeration rate, were used to see their influence on the production of biomass and saponins. The culture poisoning technique was used to determine the antifungal activity of the SC-2 and SC-3 saponins in vitro. Likewise, the shear or hydrodynamic stress of 273.6 mN/m² were calculated based on the Reynolds Number. The oxygen supply (OTR) was always greater than the demand (OUR) for all the aeration rate evaluated. Dry weight values of 8.6 gDW/L and a concentration of 2.7 mg/L and 187.3 mg/L of the saponins SC-2 and SC-3 respectively were obtained with an air flow of 0.1 vvm. In addition, it was possible to inhibit the growth of phytopathogenic fungi in vitro by up to 93%, while in vivo it was possible to reduce the infections of strawberry seeds inoculated with phytopathogens, obtaining up to 94% of germinated seeds. This information will facilitate the rational operation of the bioreactor culture system that produces secondary metabolites.

Antimicrobial, Antioxidant Activities, and HPLC Determination of the Major Components of Verbena carolina (Verbenaceae)

Verbena carolina L. (Verbenaceae) is used as a decoction in Mexican folk medicine with applications against digestive problems and for dermatological infections. The present work firstly reported HPLC analysis, as well as the free radical scavenging capacity of the extracts and isolated compounds. Antimicrobial analyses of these substances against the bacteria Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Salmonella typhi and the fungi Candida albicans, Trichophyton mentagrophytes and T. rubrum were also tested, as well as the acute oral toxicity in mice of aqueous extracts. Major secondary metabolites in V. carolina extracts were isolated by conventional phytochemical methods which consisted of three terpenoids ((1), (3) and (4)) and four phenolic compounds ((2), (4)-(6)). Their contents were determined by HPLC in six different samples from different locations. The results indicated that ursolic acid (1), hispidulin (2), verbenaline (3), hastatoside (4), verbascoside (5), hispidulin 7-O-β-d-glucuronopyranoside (6) and pectolinaringenin-7-O-α-d-glucuronopyranoside (7) were the main constituents and ranged from 0.17 to 3.37 mg/g of dried plant, with verbascoside being the most abundant and with a significant antioxidant activity in reactive oxygen species (ROS). Hispidulin was the only active compound against T. mentagrophytes and T. rubrum. The aqueous extract showed no significant toxicity (LD₅₀: > 5000 mg/mL). To our knowledge, this is the first comprehensive report of the chemical characterization of V. carolina and also of the activity of its constituents towards reactive oxygen species and dermatophytes, and its safety for consumption.

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").

Antifungal Saponins from the Maya Medicinal Plant Cestrum schlechtendahlii G. Don (Solanaceae)

Bioassay-guided fractionation of the crude extract (80% EtOH) of the leaves of Cestrum schlechtendahlii, a plant used by Q'eqchi' Maya healers for treatment of athlete's foot, resulted in the isolation and identification of two spirostanol saponins (1 and 2). Structure elucidation by MS, 1D-NMR, and 2D-NMR spectroscopic methods identified them to be the known saponin (25R)-1β,2α-dihydroxy-5α-spirostan-3-β-yl-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-galactopyranoside (1) and new saponin (25R)-1β,2α-dihydroxy-5α-spirostan-3-β-yl-O-β-D-galactopyranoside (2). While 2 showed little or no antifungal activity at the highest concentration tested, 1 inhibited growth of Saccharomyces cerevisiae (minimum inhibitory concentration (MIC) of 15-25 μM), Candida albicans, Cryptococcus neoformans, and Fusarium graminearum (MIC of 132-198 μM).

Toxicology, genotoxicity, and cytotoxicity of three extracts of Solanum chrysotrichum

ETHNOPHARMACOLOGICAL RELEVANCE

Infusions of Solanum chrysotrichum (Schldl.) or "sosa" are employed in Traditional Mexican Medicine for the local and systemic treatment of skin and mucosal infections. Different studies have verified its antifungal effectiveness and therapeutic safety in superficial mycosis caused by dermatophytes or yeasts, and have identified a group of spirostanic saponins, denominated SC-2-SC-6, as responsible for the antifungal activity. Of these, SC-2 is the most active molecule. Electron microscopy studies showed that SC-2 disintegrates cell wall and internal membranes of the fungi studied. In order to continue the systematic study of Solanum chrysotrichum, the goal of the present study was to evaluate the toxicity, genotoxicity, and cytotoxicity of the three different extracts of Solanum chrysotrichum.

MATERIALS AND METHODS

From the dried leaves of Solanum chrysotrichum, we obtained the aqueous, hydroalcoholic, and ethanolic extracts. Saponins (SC-2-SC-6) were quantified by High-performance liquid chromatography (HPLC). For the toxicology study, we formed four groups: three experimental groups, treated with each of the extracts at 1-g/kg doses per os (po) during 4 weeks, and a negative control group treated with the vehicle. For the genotoxicity study, we added another group, which was treated with cyclophosphamide for 1 week. The cytotoxicity study was carried out with international methods and employing the nasopharyngeal cancer (KB) and breast cancer (MDA) cell lines.

RESULTS

The three evaluated extracts did not modify either of the behavioral parameters, and on the hepatic-function biochemical tests (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]), did not showed significant increase on comparing to placebo. The genotoxicity parameters did not exhibit differences between the experimental groups and the placebo (control) group. Histologic analysis showed that the three extracts caused amyloidosis and moderate necrosis in liver, and focal tumefaction in kidney, as well as significant, but clinically irrelevant, elevations of creatinine with the aqueous and hydroalcoholic, but not with the ethanolic, extracts. In addition, the aqueous and ethanolic extracts exhibited interesting cytotoxic activity against the KB cell line.

CONCLUSIONS

At the doses administered, the ethanolic extract of Solanum chrysotrichum showed a slightly toxic effect on liver and kidney, without biochemical or genotoxic repercussions and with cytotoxic activity against the KB cell line.

Myo-inositol-derived glycolipids with anti-inflammatory activity from Solanum lanceolatum

Lanceolitols A1-A7 (1-7) and B1-B7 (9-15), two series of new myo-inositol-derived glycolipid analogues, in which a sugar moiety is replaced by a fatty acid esterified myo-inositol moiety, were isolated from the leaves of Solanum lanceolatum. Their structures were elucidated on the basis of spectroscopic analysis (1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC, and HRFABMS), as well as chemical analysis. All the compounds showed in vivo anti-inflammatory activity against ear edema in mice produced by 12-O-tetradecanoylphorbol-13-acetate (TPA). In vitro enzyme inhibition studies showed that the mixture of lanceolitols A1-A7 inhibited by 58.56% phospholipase A2 from bee venom, while the mixture of lanceolitols B1-B7 was cyclooxygenase-2 (COX-2) inhibitors (IC50 = 237 microM).

Biological activities and distribution of plant saponins

Plant saponins are widely distributed amongst plants and have a wide range of biological properties. The more recent investigations and findings into their biological activities were summarized. Isolation studies of saponins were examined to determine which are the more commonly studied plant families and in which families saponins have been identified.

Antimycotic spirostanol saponins from Solanum hispidum leaves and their structure-activity relationships

A new spirostanol saponin, together with three known saponins, were isolated from the leaves of Solanum hispidum. The structure of the new saponin was elucidated as 6alpha-O-beta-D-quinovopyranosyl-(25S)-5alpha-spirostan-3beta-ol (1) on the basis of spectroscopic analysis (1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC, and HRFABMS). All of the isolated compounds showed antimycotic activity. The most active compound was 6alpha-O-[beta-D-xylopyranosyl-(1-->3)-beta-D-quinovopyranosyl]-(25S)-5alpha-spirostan-3beta-ol (2) (MIC = 25 microg/mL against both Trichophyton mentagrophytes and T. rubrum). The structure-activity relationships of the isolated compounds and those isolated from S. chrysotrichum are discussed.

Herbal medicines for treatment of fungal infections: a systematic review of controlled clinical trials. Phytomedizin zur Behandlung von Pilzinfektionen: Ubersicht und Bewertung kontrollierter klinischer Studien

Traditional medicine has made use of many different plant extracts for treatment of fungal infections and some of these have been tested for in vitro antifungal activity. This systematic review evaluates antifungal herbal preparations that have been tested in controlled clinical trials. Four electronic databases were searched for controlled clinical trials of antifungal herbal medicines. Data were extracted in a standardized manner by two independent reviewers and are reviewed narratively. Seven clinical trials met our inclusion criteria. Tea tree oil preparations were tested in four randomized clinical trials and some positive outcomes were attributed to the intervention in all trials. Solanum species (two trials) and oil of bitter orange preparations (one trial) were compared with conventional treatments. In all cases encouraging results were reported. There are few controlled clinical trials of herbal antifungal medicines. The most thoroughly clinically tested is tea tree oil, which holds some promise. All herbal remedies require further investigation in rigorous clinical trials.