Abstract:
Cutaneous leishmaniases (CL) is endemic in more than 88 countries worldwide.
Zoonotic cutaneous leishmaniasis in Kenya is caused by Leishmania major. Currently
used drugs like pentostam, Amphotericin B are expensive, toxic and require
prolonged use. Combination therapy prevents drug resistance and reduces toxicity. In
addition, herbal extracts can be safe and cheaper. Allium sativum and Aloe
secundiflora water extracts have shown to have antileishmanial activities. In this
study, the efficacy of combination therapy using A. sativum and A. secundiflora
against L. major in BALB/c mice was studied using both intraperitoneal and oral
routes of administration. The standard drug pentostam and phosphate buffered saline
were used as positive and negative controls respectively. T-test and ANOVA were
used for data analysis and P-value of < 0.05 was considered significant. Plant
materials were dried, ground, soaked in water at 75oC for 1 hour, filtered then freeze
dried. The minimum inhibitory concentrations (MICs) of aqueous extracts of A.
secundiflora (AF) and A. sativum (AS) were 2000 μg/ml and 5000 μg/ml and IC50
were 467.09μg/ml and 457.88μg/ml respectively while the IC50 for their combination
at ratio (1:1) was 391.79 μg/ml as compared to MICs of 12.5μg/ml and IC50 of
108.58μg/ml for pentostam. The combination therapy had Infection rate (IR) of 17%
and multiplication index (MI) of 48.65% compared to pentostam with an IR=21% and
MI=11.64%. The combination therapy reduced the footpad lesion size significantly (P
< 0.05) like the pentostam control drug and no significant nitric oxide stimulated. The
oral and intraperitoneal combination treatment reduced spleen amastigotes in mice by
55.48% and 64.13% corresponding to total Leishman Donovan Units (LDU) of 18.23
± 0.90 and 14.69 ± 1.33 respectively compared to pentostam 94.58% and LDU of
2.22±0.13. In summary, the combination therapy was active against L. major parasite,
by reducing spleen parasite load significantly but did not prevent visceralization as
amastigotes were seen in spleen smears. This study recommends the health sector to
consider developing therapeutic products from the test plants for the treatment of CL
in poverty stricken leishmaniases endemic areas of Kenya
