Bioactive chemical constituents from Uvaria Rufa and Mitrephora Maingayi

Abstract

Investigation of the chemical constituents of Uvaria rufa (family Annonaceae) led to the isolation of eighteen compounds including cyclohexene derivatives, triterpenoids, flavonoids and an aromatic ester. From the leaves of this plant, five cyclohexene derivatives including (-)-pipoxide, 1-epizeylenol, ellipeiopsol B, zeylenol and microcarpin B, were isolated together wih a series of flavonoid glycosides including rutin, isoquercitrin, kaempferol 3-[omicron]-[beta]-D-glucopyranoside, astragalin and quercetin 3-[omicron]-[beta]-D-glucopyranoside-6-acetate. From the stems, three flavones including tectochrysin, 7-[omicron]-methylwogonine, and 6,7-[omicron],[omicron]-dimethylbaicalein, two flavanones (2,5-dihydroxy-7-methoxyflavanone and eriodictyol), two triterpenoids [glut-5(6)-ene-3[beta]-ol and taraxerol] and benzyl benzoate were isolated. Similar study on another annonaceous plant, Mitrephora maingayi, afforded ten of its constituents including one sesquiterpenoid (spathulenol), two diterpenoids (kaurenoic acid and didymooblongin) and three lignans [(+)-epieudesmin, (+-)-eudesmin and magnone A] from the leaves, whereas a diterpene acid (pimaric acid), two oxoaporphine alkaloids (liriodenine and oxostephanine), and a flavanone (pinocembrin) were obtained from the extraction of its stems. Tectochrysin was mildly toxic against human small cell lung carcinoma (NCI-H187) cell line, whereas 6,7-[omicron],[omicron]-dimethylbaicalein was cytotoxic to breast cancer (BC) cell line. Kaurenoic acid was weakly active against BC cell line, while both oxoaporphine alkaloids, liriodenine and oxostephanine, were strongly cytotoxic against KB and BC cell lines. Diverse types of compounds from these two plants were active against Mycobacterium tuberculosis H37Ra. Zeylenol, taraxerol, benzyl benzoate, 6,7-[omicron],[omicron]-dimethylbaicalein and eriodictyol from U. rufa, together with kaurenoic acid, (+)-epieudesmin, liriodenine, oxostephanine and pinocembrin from M. maingayi exhibited antituberculosis activity. Zeylenol, 6,7-[omicron],[omicron]-dimethylbaicalein and oxostephanine showed certain degrees of anti-herpes simplex activity. Quercetin 3-[omicron]-[beta]-D-glucopyranoside-6-acetate and isoquercitrin were shown to be more potent inhibitors of Advanced Glycation End-product (AGE) formation than quercetin as the positive control.