Survival of worm masses of Onchocerca ochengi in gerbils and hamsters: implications for the development of an in vivo macrofilaricide screening model

Onchocerciasis, the second leading infectious cause of blindness, afflicts approximately 21 million people globally. Its control is limited to the use of the microfilaricidal drugs, ivermectin and moxidectin. Both drugs are unable to kill the adult worms which can survive for up to 15 years in patients, justifying the urgent need for potent and novel macrofilaricides that kill adult worms. The development of such drugs has been hindered by the lack of an appropriate small laboratory animal model to evaluate potential drug candidates in vivo. This study assessed the survival of O. ochengi female worms and their embryos over time in two laboratory rodents: gerbils and hamsters and tested using "proof-of-concept" studies, whether known macrofilaricidal drugs can kill these worms. Animals were surgically implanted with mechanical or collagenase-liberated O. ochengi worm masses, and necropsied at various time points to test for survival. Recovered worm masses were assessed for viability by biochemical analysis (MTT/formazan assay) or fecundity (embryogram). Flubendazole (FBZ) administered at 20 mg/kg body weight was used to validate both rodent models. By day 26 post-implantation of 15 worm masses, a median of 7.00 (4.00-10.00) was recovered from hamsters, and 2.50 (2.00-4.00) from gerbils. Worm masses recovered from gerbils were mostly disintegrated or fragmented, with significantly higher fragmentation observed with collagenase-liberated worm masses. FBZ had no significant effect on the number of worm masses recovered, but enhanced embryo degradation in gerbils and reduced worm mass viability in hamsters. This exploratory study has revealed the gerbil and hamster as permissible rodents to adult female worms of O. ochengi. The hamsters appeared to maintain the worms longer, compared to gerbils.

Antioxidant content and activity of stem and leaf extracts of Gouania longipetala Hemsl. (Rhamnaceae)

Background

Gouania longipetala Hemsl. is a scandent shrub used in traditional medicine for the management of different ailments such as gout, female infertility, heart diseases, diabetes, and malaria. Pathophysiology of the diseases is generally associated with oxidative stress. Antioxidant properties of G. longipetala have not yet been well elucidated.

Aims

This study aimed to evaluate the antioxidant content and antioxidant activity of methanol extracts from the plant's stems and leaves.

Materials and methods

Methanol extracts from the plant stems and leaves were screened for phytochemical components with antioxidant properties (Vitamin C, total phenolics, and flavonoids). The antioxidant reducing power of the extracts as well as its effects on lipid peroxidation and catalase were also evaluated in vitro using biochemical assays.

Results

Leaf extract was richer than stem extract in different antioxidants such as Vitamin C, phenolics, and flavonoids. Both leaf and stem extracts showed similar inhibitory effect on lipid peroxidation and stimulatory effect on catalase activity, while leaf extract had higher ferric antioxidant effect than stem extract.

Conclusion

Both extracts from G. Longipetala possessed antioxidant content, though activities with leaf extract displayed higher antioxidant properties than stem extract.