Hernandia cytotoxic activity

Only three iw-aporphine alkaloids (V.1-V.3) were isolated from the two Hernandia species found in Taiwan, the trunk bark of H. nymphaeifolia (Presl.) Kubitzki (25,34) and the root bark of H. ovigera L. (35,36). Two of them [ovihemangerine (V.2) and oviisocorydine (V.3)], possess cytotoxic activity in vitro against human colon cancer cell lines (25) (Table II). (+ )-Ovigeridimerine (V.l), at 50.0 pM, does not inhibit in vitro the platelet aggregation induced by arachidonic acid, collagen, and PAF (13) and the vasorelaxing effect caused by and norepinephrine (22). 

Isoquinoline alkaloids are formed by the reaction of phenylethylamine and formaldehyde, followed by cyclization (28). Menachery has reviewed the occurrence and properties of this structural type of alkaloids (49). In the Hernandiaceae, only five such alkaloids (XI.1-XI.4 and XII.l) have so far shown restricted occurrence in a few species of Hernandia (Table I). Among them, A-methylcorydaldine (XI.l) showed cytotoxic activity in vitro against P-388, CA-KB-16, CA-A549 cells, and the human colon cancer cell line HT-29 (25) and northalifoline (XI.3) exhibited weak in vitro cytotoxity against CA-A549 cells (26) (Table II). 

Five isoquinoline alkaloid dimers with pavine and tetrahydrobenzylisoquinoline moieties, known as hervelines A-D (VIII.1-VIII.4) and HB (VIII.5), have been isolated from the stem bark of Hernandia voyronii Jum. (8,9,48), used as an adjuvant to chloroquine in Malagasy herbal practice and against chronic malaria (8,9). Two of them, harvelines B (VIII.2) and C (VIII.3) reversed in vitro chloroquine resistance to the resistant strain of P. falciparum (9) and exhibited moderate antimalarial activity (8,9,48). Harveline HB (VIII.5), an alkaloid whose structure has not been determined, also potentiated the effect of chloroquine and showed weak in vitro cytotoxicity against HeLa cells (48). 

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