Collagen synthesis-promoting and collagenase inhibitory activities of constituents isolated from the rhizomes of Picrorhiza kurroa Royle ex Benth.

Three new acylated phenylethanoid glycosides, kurroaosides A (14), B (15), and C (16), and a new acylated cucurbitane-type triterpene glycoside, kurroaoside D (17), were isolated from a methanol extract of the rhizomes of Picrorhiza kurroa Royle ex Benth. (Plantaginaceae) along with 29 known isolates including 10 acylated phenylethanoid glycosides (18-27), three cucurbitane-type triterpene glycosides (32-34), and a nortriterpene glycoside (35). The structures of these new compounds (14-17), including their stereochemistry, were determined based on chemical and physicochemical evidence derived from NMR and MS analysis. Among the isolates, acylated iridoid glycosides, picrosides I (8), II (9), III (10), and IV (11) and 6-feruloylcatalpol (12), phenylethanoid glycosides (14-16), triterpene glycosides, cucurbitacin B 2-O-ß-D-glucopyranoside (32) and 25-acetoxy-2-ß-D-glucopyranosyloxy-3,16,20-trihydroxy-9-methyl-19-norlanosta-5-en-22-one (35), and an acetophenone glycoside, picein (36), significantly promoted collagen synthesis at 10-30 µM, with no cytotoxicity being observed at the effective concentrations. Furthermore, acylated phenylethanoid glycosides, calceolarioside A (19, IC50 = 69.2 µM), plantamajoside (20, 51.8 µM), isoplantamajoside (21, 76.8 µM), and scroside E (23, 65.5 µM), exhibited collagenase inhibitory activity equivalent to that of positive agents caffeic acid (75.6 µM) and epigallocatechin 3-O-gallate (75.4 µM).

Acylated iridoid glycosides with hyaluronidase inhibitory activity from the rhizomes of Picrorhiza kurroa Royle ex Benth.

Seven new acylated iridoid glycosides, picrorhizaosides A-G (1-7), were isolated from the methanol extract of the rhizomes of Picrorhiza kurroa Royle ex Benth. (Plantaginaceae), in addition to six known iridoid glycosides (8-13). The structures of these new iridoids, including their stereochemistry, were determined based on chemical and physicochemical evidence derived from NMR and MS analysis. Of the isolates, picrorhizaosides D (4, IC50 = 43.4 µM) and E (5, 35.8 µM); picrosides I (8, 60.7 µM), II (9, 22.3 µM), and IV (11, 59.2 µM); and minecoside (13, 57.2 µM), exhibited a similar or stronger hyaluronidase inhibitory activity than those of the antiallergic medicines disodium cromoglycate (64.8 µM), ketotifen fumarate (76.5 µM), and tranilast (227 µM).