Performance evaluation of topical formulations of the crude extracts of <i>L. adoensis</i> and <i>O. rochetiana</i>

Abstract

Lippia adoensis and Olinia rochetiana are traditionally used in the form of topical applications for the treatment of various skin disorders in Ethiopia. In view of their traditional uses and proven antimicrobial activities, the crude extracts of the two botanicals were incorporated into various formulation bases having different degrees of hydrophilicity and/or lipophilicity. The performances of the resulting topical formulations were then evaluated using agar well diffusion technique. The results indicated that water miscible (hydrophilic) formulations are superior in performance to water immiscible (hydrophobic) ones. The most lipophilic ointment (petrolatum ointment) showed virtually no activity indicating that the active compound(s) of the herbal drugs could not be released from this formulation. Some formulations of the herbal drugs showed relatively comparable activities with different topical antiseptic products locally available in the market. L. adoensis in sodium laurate monostearin cream base showed a zone of inhibition of 25 ± 0.9 against S. aureus, which is even better than that of gentamycin (21 ± 1.0) against the same organism. Similarly, O. rochetiana, in the same base, showed a zone of inhibition of 65 ± 2.5 against T. menthagrophytes, which is by far better than any of the topical antifungal agents tested. From among the marketed topical antifungal agents clotrimazole gave the maximum zone of inhibition (47 ± 2.5. The traditional claims attributed to these herbal drugs by the local people for the treatment of topical skin disorders is partly justified by the different degrees of antimicrobial activities exhibited by topical formulations of these botanicals against the selected strains of bacteria and fungi which are known to be common causative agents for different types of skin infections.

Keywords: Lippia adoensis, Olinia rochetiana, topical formulations, performance evaluation, antimicrobial activity

Ethiopian Pharmaceutical Journal, vol. 22 (2004): 15-26