Phytochemical evaluation, embryotoxic, and teratogenic effects of Buwakan (Decalobanthus peltatus (L.) A.R.Simões & Staples) leaf extracts on duck embryo.

Decalobanthus peltatus is a woody vine that is commonly utilized in traditional Southeast Asian medicinal preparations. Despite the documented therapeutic uses of D. peltatus, there is hardly any information regarding its toxic effects on its consumers. In this study, crude leaf extracts (aqueous, methanol, ethyl acetate, and hexane) from D. peltatus were prepared and evaluated for their embryotoxicity and teratogenic effects. Phytochemical screening of bioactive compounds from the plants showed the presence of alkaloids, flavonoids, saponins, steroids, and tannins. In addition, investigations on the toxicity of the crude leaf extracts were determined using brine shrimp lethality assay, in which the LC50 was calculated. Results showed that the ethyl acetate leaf extract was the most toxic among the crude leaf extracts, with an LC50 of 14.54 ppm. Based on this result, ethyl acetate leaf extract was treated on duck embryos, and the alteration of vascular branching patterns in the chorioallantoic membrane was quantified. Gross morphological and histological analysis of the skin tissues from the treated duck embryos were also examined. We found significant reduction of primary and tertiary vessel diameters in the duck embryos treated with ethyl acetate leaf extracts in both concentrations compared to the control group. Treated duck embryos exhibited gross malformations, growth retardation, and hemorrhages on the external body surfaces at 1000 ppm. Histopathological analysis of the skin tissues from the 14-day-old treated duck embryos showed a reduced number of feather follicles compared to the control group. These results suggest that D. peltatus crude leaf extracts present risks when taken in significant dosages and comprehensive toxicity testing on therapeutic herbs should be performed to ensure their safety on the consumers.