Evaluation of process procedures of selected medicinal plants used for treating malaria fevers in Tororo district

Abstract

Background: Despite widespread utilization of medicinal plants globally, there is insufficient documentation regarding their efficacy and standard processing procedures (SPP)-leading to products with variable levels of active substances and unpredictable pharmacological action. The purpose of this study was to determine if selected antimalarial herbs from Tororo, Uganda, are processed as per WHO requirements, factors influencing the manner of preparation and to determine efficacy, quality and levels of active principles of products when SPP are not followed. Methods: Cross-sectional studies were used to document knowledge, attitude and practices (KAP) of herbalists regarding SPP. Laboratory assays were used to determine antiplasmodial activities and safety of the study botanicals. Method (OPQ/STP/FP-3144-1/5) at Med Pharm Uganda was used for phytochemical analyses, herbal Plumbagin and Phyllanthin contents as well as chemical and physical stability parameters. Standard laboratory methods were used to determine efficacy, biological and toxicological parameters of herbal powders in a six month stability study. Results: From 106 herbalists, 100 had scanty knowledge about SPP while 100% opted not to label their herbal products. Furthermore, herbalist practices from plant identification to storage are still below WHO standards. Plumbago zylenica extracts processed by indigenous knowledge (IK) displayed high in vitro antiplasmodial activity on chloroquine sensitive (3D7) strains (IC50 of 4.2 - 4.3μg/ml). The in vitro antiplasmodial activity of IK prepared Phyllanthus amarus extracts was low compared to those prepared according to WHO (IC50= 12.15μg/ml and 3.533μg/ml respectively). On the other hand, Phyllanthus amarus shoot extracts exhibited significant in vivo antimalarial activities targeting trophozoite stage of the parasite. Plumbagin content in Plumbago zylenica IK processed root was significantly higher than those meeting WHO requirements (0.38 ± 0.015μg/ml and 0.35 ± 0.01/ μg/ml respectively), P<0.05 while P. amarus IK processed shoot contained less phyllanthin compared to those meeting WHO requirements (1.972 ± 0.24μg/ml and 4.286 ± 0.03/ μg/ml respectively), P<0.05). Both P. zylenica root and P. amarus shoot unpreserved powders are stable for 6 months at 25±5oC and RH of 65 ± 5%. However, the quality of the IK processed herbs is low due to unacceptable levels of aflatoxins. Conclusion: This study has documented KAP regarding herbal SPP in Tororo. The Ugandan Phyllanthus amarus shoot has demonstrated in vivo antimalarial activity against Plasmodium berghei trophozoites. Both P. zylenica root and P. amarus shoot unpreserved powders are stable for 6 months at 25±5oC and RH of 65 ± 5%. Factors influencing the manner of preparation included lack of a proactive herbalist Association, refresher courses and negative attitudes on (SPP). Recommendations: It is recommended that MoH in collaboration with the Ministries of Youth, Gender and Culture, Agriculture and Forestry as well as researchers to address issues raised in this study.