A new steroidal glycoside and fatty acid esters from the stem bark of Tectona grandis Linn

Isolation and HPLC Quantitative Determination of 5α-Reductase Inhibitors from Tectona grandis L.f. Leaf Extract

Steroid 5α-reductase plays a crucial role in catalyzing the conversion of testosterone to dihydrotestosterone, which is involved in many androgen-dependent disorders. Leaf-hexane extract from Tectona grandis L.f. has shown promise as a 5α-reductase inhibitor. The objectives of this current study were to isolate and identify 5α-reductase inhibitors from T. grandis leaves and to use them as the bioactive markers for standardization of the extract. Three terpenoid compounds, (+)-eperua-8,13-dien-15-oic acid (1), (+)-eperua-7,13-dien-15-oic acid (2), and lupeol (3), were isolated and evaluated for 5α-reductase inhibitory activity. Compounds 1 and 2 exhibited potent 5α-reductase inhibitory activity, while 3 showed weak inhibitory activity. An HPLC method for the quantitative determination of the two potent inhibitors (1 and 2), applicable for quality control of T. grandis leaf extracts, was also developed. The ethanolic extract showed a significantly higher content of 1 and 2 than found in the hexane extract, suggesting that ethanol is a preferable extraction solvent. This study is the first reported isolation of 5α-reductase inhibitors (1 and 2) from T. grandis leaves. The extraction and quality control methods that are safe and useful for further development of T. grandis leaf extract as an active ingredient for hair loss treatment products are also reported.

Identification of β-hydroxy fatty acid esters and primary, secondary-alkanediol esters in cuticular waxes of the moss Funaria hygrometrica

The plant cuticle, a multi-layered membrane that covers plant aerial surfaces to prevent desiccation, consists of the structural polymer cutin and surface-sealing waxes. Cuticular waxes are complex mixtures of ubiquitous, typically monofunctional fatty acid derivatives and taxon-specific, frequently bifunctional specialty compounds. To further our understanding of the chemical diversity of specialty compounds, the waxes on the aerial structures of the leafy gametophyte, sporophyte capsule, and calyptra of the moss Funaria hygrometrica were surveyed. Respective moss surfaces were extracted, and resulting lipid mixtures were analyzed by gas chromatography-mass spectrometry (GC-MS). The extracts contained ubiquitous wax compound classes along with two prominent, unidentified classes of compounds that exhibited some characteristics of bifunctional structures. Microscale transformations led to derivatives with characteristic MS fragmentation patterns suggesting possible structures for these compounds. To confirm the tentative structure assignments, one compound in each of the suspected homologous series was synthesized. Based on GC-MS comparison with the authentic standards, the first series of compounds was identified as containing esters formed by β-hydroxy fatty acids and wax alcohols, with ester chain lengths varying from C42 to C50 and the most prominent homolog being C46. The second series consisted of fatty acid esters of 1,7-alkanediols, linked via the primary hydroxyl group, with ester chain lengths C40-C52 also dominated by the C46 homolog. The β-hydroxy acid esters were restricted to the sporophyte capsule, and the diol esters to the leafy gametophyte and calyptra. Based on their homolog and isomer distributions, and the presence of free 1,7-triacontanediol, possible biosynthetic reactions leading to these compounds are discussed.

Antioxidant lignans and chromone glycosides from Eurya japonica

Four new 8,8',7,2'-lignans, (+)-ovafolinin B-9'-O-β-d-glucopyranoside (1), (-)-ovafolinin B-9'-O-β-d-glucopyranoside (2), (+)-ovafolinin E-9'-O-β-d-glucopyranoside (3), and (-)-ovafolinin E-9'-O-β-d-glucopyranoside (4), two neolignans, eusiderin N (5) and (7S,8R)-3,5,5'-trimethoxy-4',7-epoxy-8,3'-neolignan-9,9'-diol-4-O-β-d-xylopyranoside (6), and two new chromone glycosides, 5,7-dihydroxy-4H-chromen-4-one-3-O-β-d-glucopyranoside (7) and 5,7-dihydroxy-4H-chromen-4-one-3-O-β-d-xylopyranoside (8), together with 25 known compounds, were isolated from the stems of Eurya japonica. Structural elucidation of compounds 1-8 was established by spectroscopic methods, especially 2D NMR techniques, electronic circular dichroism data, and comparison with reported data. The isolates were evaluated for antioxidant and anti-NO production activities. Compounds 1, 2, 12-20, and 29 (ED50 23.40 μM for 1) demonstrated potent antioxidant activity compared to the positive control α-tocopherol (ED50 27.21 μM). On the other hand, compounds 1, 2, 7-9, 12-20, and 32 showed only weak anti-NO production activity when compared to the positive control quercetin.