Asian Research Thesis Index

Abstract

The main focus of this PhD research project is the isolation, structure elucidation and bioassay of steroidal alkaloids of medicinally important plant Sarcococca saligna, belongs to Buxaceae family. Five compounds were isolated from the chloroform fraction of S.saligna through phytochemical investigation i.e. Alkaloid-C (1), Dictyophlebine (2), Sarcovagine-D (3), Saracodine (4) and Holaphylline (5). The structure of compounds was determined through modern spectroscopic techniuqes. These steroidal alkaloids were then screened for various In-vivo biological assays such as hepatoprotective and antidiabetic, while also tested In-vitro biological activities such as immunosuppresent, antibacterial, antifungal, phtotoxicity, insecticidal, cytotoxicity and leshmanicidal activity. The compounds were also investigated as steroidal aromatase inhibitors through molecular docking studies against breast cancer. The selected steroidal alkaloids were screened for In-vivo hepatoprotective and antidiabetic activities. The compounds 1, 3 and 5 markedly decreased hepatic injury by CCl4-injury inducer and mixed inflammatory penetration. Therefore, we explored and suggest that steroidal alkaloids from S.saligna could be excellent hepatoprotective agents. The isolated steroidal alkaloids were also tested for the antidiabetic potential and the result showed that compounds 3 and 5 reduced the glucose level significantly in blood and also make better others diabetes associated complications. The isolated steroidal alkaloids were screened for In-vitro biological assays. Compound 1, 3 and 5 were screened for immunosuppressant activity. Compounds showed inhibitory activities of T-cell proliferation in the range of 78 to 95% and also inhibit IL-2 production which means the tested compounds were excellent immunosuppressive agents. The compounds 2, 3 and 5 were screened for antibacterial activity. The compound 2 showed significant antibacterial activity against S.aureus (79%). The compound 3 showed significant antibacterial activity against P.aeruginosa (79%), while compound 5 showed good antibacterial activity against B.subtilus (72%) and P.aeruginosa (69%) respectively. The isolated steroidal alkaloids were screened for antifungal activity against various pathogenic fungi and showed low to moderate antifungal actions. Compounds 1 and 3 showed low antifungal activity while compound 5 showed moderate antifungal activity against selected pathogenic fungi. The selected steroidal alkaloids were also screened for antileshmanial activity. Compounds 4 showed moderate antileshmainal activity while compound 5 showed significant inhibition against the promastigotes of L. tropica. The phytotoxic effect of compound 5 was observed maximum 66%, while 1 and 2 showed low activity at different concentration level. The isolated steroidal alkaloids were tested for insecticidal activity and among them compound 5 showed maximum activity 65% against T.castaneum, while showed low activity against R.dominica and C.analis (20% and 10%) respectively. The selected steroidal alkaloids were screened for antioxidant actions in which compounds 3 and 5 showed significant antioxidant actions and radical scavenging activity increased up to 78% and 80%. The isolated compounds were also screened for anticancer activity in which compound 2 found to be more active with IC50 value 6.13±0.345, while compound 1 showed moderate anticancer activity with IC50 values 12.98±0.235 against HeLa cells lines. The compounds were to explore as a new steroidal aromatase inhibitors through molecular docking studies in which compound 5 and 1 were active against aromatase enzyme in breast cancer could provide new lead compounds.

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