PHYTOCHEMICAL AND STRUCTURAL STUDIES ON THE CHEMICAL CONSTITUENTS OF TAXUS WALLICHIANA, TANACETUM GRACILE, JOLYNA LAMINARIOIDES AND OTHER MARINE ALGAE
ABSTRACT This thesis describes phytochemical and biological investigations on two terrestrial medicinal plants, Taxus wallichiana and tanacetum gracile, and three marine algae, Jolyna Laminarioides, Iyengaria stellata and Melanothamnus afaqhusainii. Phytochemical studies on Taxus wallichiana yielded three new taxane diterpenoids, namely 5a, 7B, 10B, 13a-tetrahydroxy-2a,9a, 15-triacetoxy-11(15-1)abeo-taxa-4(20),11-diene (82) and 7,9,10,13-tetradeacetyl-abeo-baccatin IV (84). Six known compounds B-amyrin (93) 14a-taraxeran-3-one (94) 14a-taraxeran-3a-ol (95) octacosyl-p-coumarate (96) octacosanyl ferulate (97) and 3-hydroxy-4-methoxybenzaldehyde (98) were isolated for the first time from Tanacetum gracile. Furthermore, chemical studies on Jolyna Laminarioides yielded two new compounds, methyl-2-[propanamide-2ÃÂÃÂ¢ÃÂÃÂÃÂÃÂ-methoxycarbonyl] benzoate (102) and 2-pyridine carboxamide (103) along with four known compounds fuconsterol (104) 9-B-(D-ribofuranosyl) adenine (105) 1-phyten-3-ol (106) and p-formylphenol (107) which were isolated for the first time from this alga. Four known compounds saringosterol (108) Ioliolide (109) propyl-4-hydroxybenzoate (105) and methyl-4-hydroxybenzoate (106) were isolated for the first time from Iyengaria stellata whereas two new compounds 3,4,5-trimethylaniline (116) and 1-amino-3-phenylacetone (117) and one known compound harmine (118) were isolated for the first time from Melanothamnus afaqhusainii. The structures of these compounds were determined using extensive spectroscopic techniques.