Khem Raj Joshi

Two new diacetylene glycosides: bhutkesoside A and B from the roots of Ligusticopsis wallichiana

Abstract Two new diacetylene glycosides: bhutkesoside A (1) and B (2), along with 10 known compounds, i.e. falcarindiol (3), chlorogenic acid (4), 5-O-p-coumaroyl-quinic acid (5), 3,5-di-O-caffeoyl-quinic acid (6), 4-hydroxy-7-methoxy-phenylethanol (7), ferulic acid (8), dehydrodiconiferyl alcohol-4-O-β-d-glucopyranoside (9), 5,7-dihydroxy-2-methylchromone-7-O-rutinoside (10), schumanniofioside B (11) and marmesinin (12) were isolated from the roots of Ligusticopsis wallichiana (DC) Pimenov & Kljuykov (Apiaceae), commonly known as ‘Bhutkesh’ in Nepal. The structures were determined on the basis of spectroscopic data. Compounds 4 and 6 showed potent antioxidant activity on DPPH free radical scavenging assay.

Dhasingreoside: new flavonoid from the stems and leaves of Gaultheria fragrantissima.

A new flavonoid, dhasingreoside (1) and seven known compounds, quercetin 3-O-β-d-galacturonopyranoside (2), quercetin 3-O-β-d-galactopyranoside (3), quercetin 3-O-β-d-glucuronopyranoside (4), quercetin 3-O-α-l-rhamnopyranoside (5), (–)-epicatechin (6), salicylic acid (7) and gaultherin (8), have been isolated from the shade-dried stems and leaves of Gaultheria fragrantissima, commonly known as ‘Dhasingre’ in Nepal. The structures were elucidated on the basis of physical, chemical and spectroscopic methods. Among known compounds, five compounds (3–6 and 8) were isolated for the first time from G. fragrantissima. In vitro antioxidant activity of all the isolated compounds was evaluated by 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging assay. Dhasingreoside (1) and other compounds (2–6) showed significant free radical-scavenging activity.

Phenolic compounds from the flowers of Nepalese medicinal plant Aconogonon molle and their DPPH free radical-scavenging activities

Eleven phenolic compounds, quercetin (1), quercetin 3-O-β-d-galactopyranoside (2), quercetin 3-O-(6″-O-galloyl)-β-d-galactopyranoside (3), quercetin 3-O-(6″-O-caffeoyl)-β-d-galactopyranoside (4), quercetin 3-O-β-d-glucopyranoside (5), rutin (6) quercetin 3-O-α-l-arabinopyranoside (7), quercetin 3-O-α-l-arabinofuranoside (8), protocatechulic acid (9), gallic acid (10) and chlorogenic acid (11), were isolated from the flowers of Aconogonon molle, a Nepalese medicinal plant. Structures of these compounds were elucidated on the basis of spectroscopic methods. All these compounds were isolated for the first time from flowers, and five compounds (4, 5, 8, 9 and 11) were isolated for the first time from A. molle. All of these isolated compounds were evaluated for their in vitro antioxidant activity by using the 1,1-diphenyl-2-picrylhydrazyl radical-scavenging method. Quercetin (1), quercetin glycosides (2–8) and gallic acid (10) exhibited potent antioxidant activity.