Fengming Xu

Salaprinol and ponkoranol with thiosugar sulfonium sulfate structure from Salacia prinoides and α-glucosidase inhibitory activity of ponkoranol and kotalanol desulfate

The methanolic extract from the roots and stems of Indian Salacia prinoides and its water-eluted fraction of Diaion HP-20 column were found to exhibit inhibitory activities against α-glucosidase. From the water-eluted fraction, two new unique constituents with thiosugar sulfonium sulfate, salaprinol (1) and ponkoranol (2), were isolated together with 10 known constituents including salacinol and kotalanol. The structures of 1 and 2 were elucidated on the basis of chemical and physicochemical evidence. Furthermore, ponkoranol (2) and kotalanol desulfate (14) were found to show potent inhibitory activities against α-glucosidase.

Melanogenesis inhibitors from the desert plant Anastatica hierochuntica in B16 melanoma cells.

The methanolic extract from the whole plants of Anastatica hierochuntica, an Egyptian herbal medicine, was found to inhibit melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells. Among the constituents isolated, anastatin A, silybin A, isosilybins A and B, eriodictyol, luteolin, kaempferol, quercetin, hierochins A and B, (2R,3S)-2,3-dihydro-2-(3,4-dimethoxyphenyl)-3-hydroxymethyl-5-(2-formylvinyl)-7-hydroxybenzofuran, (+)-dehydrodiconiferyl alcohol, (+)-balanophonin, 1-(4-hydroxy-3-methoxyphenyl)-2-{4-[(E)-3-hydroxy-1-propenyl]-2-methoxyphenoxy}-1,3-propanediol, and 3,4-dihydroxybenzaldehyde substantially inhibited melanogenesis with IC(50) values of 6.1-32 microM. With regard to the mechanism of action of silybins and isosilybins, the inhibition of tyrosinase activity suggested to be important. In addition, isosilybins A and B inhibited the mRNA expression of TRP-2, but silybins A and B oppositely enhanced the mRNA expression of tyrosinase and TRP-1 and -2 at 10 and/or 30 microM, and the inhibition of phosphorylation of extracellular signal-regulated kinases (ERK1/2) is involved in the enhanced expression of mRNA, at least in part, similar to that of PD98059.

Anastatins A and B, new skeletal flavonoids with hepatoprotective activities from the desert plant Anastatica hierochuntica.

New skeletal flavonoids, anastatins A and B, were isolated from the methanolic extract of an Egyptian medicinal herb, the whole plants of Anastatica hierochuntica. Their flavanone structures having a benzofuran moiety were determined on the basis of chemical and physicochemical evidence. Anastatins A and B were found to show hepatoprotective effects on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes and their activities were stronger than those of related flavonoids and commercial silybin.

Sesquiterpenes from Curcuma comosa

From the dried rhizomes of Curcumacomosa cultivating in Thailand, 26 known sesquiterpenes were isolated: zederone, zederone epoxide, furanodienone, isofuranodienone, 1(10)Z,4Z-furanodiene-6-one, glechomanolide, dehydrocurdione, neocurdione, curdione, 7α-hydroxyneocurdione, 7β-hydroxycurdione, germacrone-1(10),4-diepoxide, germacrone, 13-hydroxygermacrone, curzerenone, curcolonol, alismol, alismoxide, zedoarondiol, isozedoarondiol, procurcumenol, isoprocurcumenol, aerugidiol, zedoalactone B, curcumenone, and curcumadione. Their structures were elucidated on the basis of physicochemical evidence. Among them, glechomanolide, curzerenone, curcolonol, alismol, alismoxide, and zedoarondiol showed no significant optical activities, so they may be artifact products during the isolation or drying process.