Leaves and roots of C. mucronata are used by some communities to treat venereal diseases, wounds and gastro-intestinal complaints such as diarrhoea and dysentery [1, 8]. T. villosa is reported to be toxic to animals and fish; however, in India it is used in the treatment diabetes mellitus . There is no larvicidal activity is reported before for C. mucronata and T. villosa. Therefore, in this study, larvicidal, antimicrobial and brine shrimp activities were evaluated to determine the medicinal value and safety of these plant species.
The larvicidal activity assay was used to predict the presence of bioactive compounds that are able to kill mosquito larvae (C. quinquefasciatus larvae) or disrupt their development towards the adult form which is responsible for disease transmission . Similarly, the brine shrimp lethality test is normally used to predict presence of toxic bioactive compounds but also possible presence of compounds with potential anticancer activity . In this regard, ethanol and dichloromethane root extracts from C. mucronata exhibited high larvicidal activity, with the highest activity observed with dichloromethane extract which had the LC50 value of 117.09 μg/mL. C. mucronata aerial part extracts did not exhibit any larvicidal activity. The extract is generally regarded as non-toxic if its LC50 is greater than 100 μg/mL in the brine shrimp lethality assay . In this case, ethanolic extract of the roots of C. mucronata had larvicidal activity but not toxic, while dichloromethane extract showed larvicidal activity but also observed to be toxic. The literature report that the root extract of C. mucronata is active against chloroquine-sensitive and chloroquine-resistant P. falciparum malaria parasites , which is transmitted by Anopheles mosquito. Mosquitoes are responsible for the spread of various vector born diseases including malaria which is found in more than 100 countries in the world . Although there are several ways of preventing the mosquito borne-diseases, one of the best option to prevent the spread of those diseases is to control mosquito vector by using larvicides. However, resistance and environment damage caused by synthetic agents have prompted for the search for environmental friendly and effective larvicides from plant sources . In this study, results have shown that ethanol extract of the roots of C. mucronata may be useful as larvicidal agent.
Based on arguments by Aligiannis et al., 2001 , extracts from C. mucronata with promising antimicrobial activity were CMAE against V. cholera (MIC = 0.391 mg/mL) and CMAD against B. anthracis (MIC = 0.195 mg/mL), S.typhi (MIC = 0.781 mg/mL), and C. neoformans (MIC = 0.195 mg/mL). Antimicrobial activities of C. mucronata collected from other parts of the world have already been documented [10, 11]. Although C. mucronata roots are used by the people of Coast region in Tanzania for treatment of fresh wounds, the antimicrobial activity of the extracts from roots was found to be generally lower than that of the extracts from aerial parts (Table 2). Therefore, the use of root extracts for treatment of fresh wound may suggests that, apart from the weak antibacterial properties, C. mucronata root extract might has other properties such as anti-inflammatory property. Furthermore, these results suggest that, the aerial parts of this plant species may substitute roots in the preparation of herbs needed in the treatment of wounds and other bacterial infection.
All ethanolic extracts of T. villosa exhibited larvicidal activity, with highest activity being in the fruit extract which had LC50 value of 53.25 μg/mL. Furthermore, extracts from leaves and twigs were not toxic to brine shrimp (LC50 > 100 μg/mL) whereas extracts from fruits and roots were very toxic to brine shrimp with LC50 < 10 μg/mL (Table 1). Interestingly, the LC50 value of twigs extract in the larvicidal activity was lower than the LC50 for brine shrimp toxicity. This suggests that, ethanolic extract from twigs may be useful as larvicides in the control of the spread of mosquito-borne diseases. This observation corroborates the earlier reports on the seeds of T. vogelii which share the same genus as T. villosa. The seeds of T. vogelii are reported to have larvicidal activity against Aedes aegti larvae .
Brine shrimp results obtained from fruits and roots support previous claims of T. villosa toxicity to animals and fish  and medicinal use of leaf extract (16). Fruit and root extracts of T. villosa were found to be very toxic with their LC50 values below that of the anticancer drug, cyclophosphamide whereas leaf and twig extracts were found to be non-toxic (Table 1). This suggests that the toxic characteristic of T. villosa is due to the fruits and roots, and strengthen the speculation for potential to yield anticancer agents (26).
The ethanolic extracts from T. villosa were also evaluated for their antimicrobial properties. The extracts with promising antimicrobial activity were from fruits against C.neoformans with MIC = 0.195 mg/mL, roots against B. anthracis with MIC = 0.195 mg/mL and leaves against E. coli with MIC = 0.781 mg/mL. When compared with other species in the same genus, most of the species reported earlier showed no or weak antimicrobial properties . Some of the reported antimicrobial activities from the genus Tephrosia are of methanolic extract from aerial parts of T. apollinea which was active against C. albicans and of aqueous extract from the entire T. purpurea which was active against S. aureus [27, 28]. Although most of the extracts from T. villosa showed weak antibacterial and antifungal activity, the good activity observed from the fruit extract against C. neoformans suggests that further studies is needed to identify bioactive compound responsible for the antimicrobial activity.