Phytochemical and Biological Investigation of an Indigenous Plant of Bangladesh, Gynura procumbens (Lour.) Merr.: Drug Discovery from Nature.

Gynura procumbens (Lour.) Merr. (Family: Asteraceae) is a tropical Asian medicinal plant found in Thailand, China, Malaysia, Indonesia, and Vietnam. It has long been utilized to treat a variety of health concerns in numerous countries around the world, such as renal discomfort, constipation, diabetes mellitus, rheumatism, and hypertension. The chemical investigation resulted in the isolation and characterization of six compounds from the methanol (MeOH) extract of the leaves of Gynura procumbens, which were identified as phytol (1), lupeol (2), stigmasterol (3), friedelanol acetate (4), ß-amyrin (5), and a mixture of stigmasterol and ß-sitosterol (6). In-depth investigations of the high-resolution 1H NMR and 13C NMR spectroscopic data from the isolated compounds, along with comparisons to previously published data, were used to clarify their structures. Among these, the occurrence of Compounds 1 and 4 in this plant are reported for the first time. The crude methanolic extract (CME) and its different partitionates, i.e., petroleum ether (PESF), chloroform (CSF), ethyl acetate (EASF), and aqueous (AQSF) soluble fractions, were subjected to antioxidant, cytotoxic, thrombolytic, and anti-diabetic activities. In a DPPH free radical scavenging assay, EASF showed the maximum activity, with an IC50 value of 10.78 µg/mL. On the other hand, CSF displayed the highest cytotoxic effect with an LC50 value of 1.94 µg/mL compared to 0.464 µg/mL for vincristine sulphate. In a thrombolytic assay, the crude methanolic extract exhibited the highest activity (63.77%) compared to standard streptokinase (70.78%). During the assay for anti-diabetic activity, the PESF showed 70.37% of glucose-lowering activity, where standard glibenclamide showed 63.24% of glucose-reducing activity.

Crispenes F and G, cis-Clerodane Furanoditerpenoids from Tinospora crispa, Inhibit STAT3 Dimerization.

Two new cis-clerodane-type furanoditerpenes, crispenes F and G (1 and 2), together with seven known compounds, were isolated from the stems of Tinospora crispa. Crispenes F and G (1 and 2) inhibited STAT3 dimerization in a cell-free fluorescent polarization assay and were found to have significant cytotoxicity against a STAT3-dependent MDA-MB 231 breast cancer cell line, while being inactive in a STAT3-null A4 cell line. These two compounds share structural similarities with a previously reported STAT3 inhibitor, crispene E, isolated from the same plant. Molecular docking studies suggested that the molecules inhibit STAT3 by interacting with its SH2 domain.

Phytochemical investigations and antioxidant potential of roots of Leea macrophylla (Roxb.).

BACKGROUND: Oleanolic acid (NZ-15), 7 α, 28-olean diol (NZ-38) and Stigmasterol (NZ-14) were isolated from the ethanolic extracts of the roots of Leea macrophylla (Family: Leeaceae) by using chromatographic analysis. This is the first report of isolation of these compounds from this plant. Their structures were constructed by spectroscopic analysis and by comparing the data with the published one. Subsequently the ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property. METHODS: The ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property by DPPH free radical scavenging assay, superoxide anion radical scavenging assay, nitric oxide radical scavenging assay, and reducing power assay. RESULTS: In the DPPH free radical scavenging assay and superoxide radical scavenging assay, the ethyl acetate soluble fraction of ethanolic extract revealed the highest free radical scavenging activity with IC50 value of 2.65 and 155.62 µg/ml, respectively as compared to standard ascorbic acid (IC50 value of 5.8 and 99.66 µg/ml). Ethyl acetate fraction also possessed highest reducing power activity with an EC50 value of 15.27 µg/ml compared to ascorbic acid (EC50 0.91 µg/ml). On the other hand, the carbon tetrachloride fraction exhibited most significant NO scavenging activity with IC50 value of 277.8 µg/ml that was even higher than that of standard ascorbic acid (IC50 value 356.04 µg/ml). In addition, the total phenolic contents of these extract and fractions were evaluated using Folin-Ciocalteu reagent and varied from 7.93 to 50.21 mg/g dry weight expressed as gallic acid equivalents (GAE). CONCLUSIONS: This study showed that different extracts of roots of L. macrophylla possess potential DPPH, superoxide, and NO free radical scavenging activities. The antioxidant activities of the plant extracts might be due to the presence of oleanolic acid, oleanolic acid derivative 7 α, 28-olean diol and stigmasterol.

Crispene A, B, C and D, Four New Clerodane Type Furanoid Diterpenes from Tinospora crispa (L.).

BACKGROUND: Tinospora crispa (L.) is used to alleviate the symptoms of diabetes mellitus in folk medicine. It is also used for hypertension and to treat malaria, remedy for diarrhea, and as vermifuge. MATERIALS AND METHODS: Stems of T. crispa were collected, sun dried for several days followed by oven dried for 24 h at a considerably low temperature and then ground into coarse powder. The powdered stems were soaked in methanol at room temperature for 14 days with occasional shaking. The extract was collected by filtration, and the solvent was evaporated under reduced pressure in a rotary evaporator to obtain a solid residue which was then subjected to fractionation using the modified Kupchan partitioning method into n-hexane, CCl4, CHCl3 and aqueous soluble fractions. The n-hexane soluble fraction was chromatographed over sephadex (LH-20) and the column was eluted with n-hexane: CH2Cl2:MeOH (2:5:1) followed by CH2Cl2:MeOH (9:1) and MeOH (100%) in order to increase the polarities. The column fractions were then concentrated and subjected to thin layer chromatography screening and the fractions with a satisfactory resolution of compounds were rechromatographed over silica gel to isolate the pure compounds. RESULTS: Four new furanoid diterpenes of clerodane types, Crispene A, B, C, and D (1-4), including one known furanoid diterpene glucoside, borapetoside E (5), were isolated from the stems of T. crispa. The structures of these compounds were elucidated by means of extensive spectroscopic analysis and by comparison of their spectral data with closely related compounds. CONCLUSION: We have reported four new furanoid diterpenes of clerodane types, including one known furanoid diterpene glucoside. This is the first report of any clerodane diterpene having olefinic bond between C-6 and C-7. SUMMARY: Crispene A, B, C, and D, four new furanoid diterpenes of clerodane types from Tinospora crispaCrispene C, an unusual furanoid diterpene with olifinic bond between C-6 and C-7First report of Crispene D as a free aglycone, though it was earlier reported as an enzymatic hydrolysis product. Abbreviation used: TLC: Thin layer chromatography, NMR: Nuclear magnetic resonance, COSY: Correlation spectroscopy, NOE: Nuclear overhauser effect, HPLC: High-performance liquid chromatography, ESI-MS: Electrospray ionization mass spectroscopy.

Cytotoxic dimeric quinolone-terpene alkaloids from the root bark of Zanthoxylum rhetsa.

Four quinolone-terpene alkaloids, chelerybulgarine (1), 2'-episimulanoquinoline (3), 2,11-didemethoxyvepridimerine B (4), and rhetsidimerine (5) were isolated from the root bark of Zanthoxylum rhetsa DC. Chelerybulgarine (1) is a C-C linked terpene alkaloid where the C-6 of dihydrochelerythrine is linked to C-11 of the sesquiterpenoid 10ß-methoxybulgarene. 2'-Episimulanoquinoline is a dimeric alkaloid containing dihydrochelerythrine and 8-methoxy-N-methylflindersine moieties, whereas 2,11-didemethoxyvepridimerine B and rhetsidimerine are dimeric prenylated quinolone alkaloids. Seven of the isolated compounds exhibited weak cytotoxicity when tested against a panel of six human stomach-cancer cell lines.

Further sesquiterpenes from Polygonum viscosum (Polygonaceae).

Two new sesquiterpenes, 4-methoxycarbonyl-7-(1-methylethyl)-6-oxo-3,3a,7,8,8a-pentahydroazulene-1-carboxylic acid (viscoazusone) and 1,4-dimethoxy-carbonyl-7-(1-methylethyl)-6-oxo-3,3a,7,8,8a-pentahydroazulene (viscoazulone), were isolated from the whole plant of Polygonum viscosum. The structures of these compounds were determined by spectroscopic means.