Plant Material. The roots of P. bussei and P. parvifolia were
collected in May 2013 from Mombasa, the coastal region, and from
western Kenya, respectively. The plant materials were identified by Mr.
P. C. Mutiso of the University of Nairobi, School of Biological Science
Herbarium, where voucher specimens (PCM-2010/048 for P. bussei
and PCM-2010/054 for P. parvifolia) have been deposited.