In this paper a number of
anticancer agents of natural origin will be presented.
Hydroxycamptothecin (
HCPT) was found to produce a strong inhibitory action on a variety of animal
tumors. It is also effective for treatment of patients with gastric
carcinoma, liver
carcinoma,
tumor of head and neck or
leukemia. Pharmacologic studies showed that it could depress S phase of
tumor cells significantly and cause formation of cellular chromatid breaks. By means of alkaline elution and nick translation methods it has been proved that
HCPT induced
DNA single strand breaks remarkably.
Homoharringtonine (HHRT) was shown to be effective against acute
leukemia. Recent experiments in
tumor-bearing mice indicated that (HHRT) could diminish
tumor metastasis. Using molecular hybridization technique it was demonstrated that (HHRT) decreased the content of c-myc
RNA in the cytoplasm but not in the nuclei.
Lycobetaine (LBT) possessed strong inhibitory effects on a number of
ascites tumors. In clinical trials it was effective against ovarian and gastric
carcinomas. It is able to intercalate into
DNA. Oxalysine (
OXL) is a new
antibiotic and shown to be effective against
tumor metastatis. When used in combination with
5-FU, its anticancer action could be enhanced. Other natural compounds such as
indirubin,
beta-elemene,
irisquinone, oridonine,
norcantharidin and PSP have been also found to possess antitumor action.