now for the info:
the herbs are foud in western africa, where they are used as male fertility drugs.
they are called hibiscus macranthus and basella alba.
rats were given a water extract for 15 days, and then tested. test levels had rose by %80, and an examination of the testes showed a rise of %136 in test synthesis. it was through direct effect on the leydig cells.
no rats died, ad no signs of toxicity were found.
the study, which can be found online is called:
'effects of aqueous extracts of hibiscus macranthus and basella alba in mature rat tesis function J enthopharmacology 65:133-39 by Moundipa F.P. et al 1999.
i will be back with the URL to the study.