Mmushi T MSc (Microbiology).pdf

traditional medicines are roots hence the plant part that is essential for the growth of a
plant is the most sensitive to harvest is one that is most exploited. Therefore collectors
must collect such parts with extreme care to ensure the plant’s survival.
Fig. 1.5. Parts of medicinal plants used in treatment of various diseases (Willcox et al., 2004).
1.3.2 Preparation of plant extracts
In traditional medicinal practice, plant extracts are prepared in various ways including
infusions, decoctions and poultices. Application of a remedy is by different routes and
methods depending on the perceived cause of the disease and condition (Masika et al.,
2000). Since water is a common solvent used by traditional healers, yet most active
compounds require solvents of vary polarity, therefore, it would seem unlikely that the
traditional healer is able to extract those compounds which are responsible for activity in
the non-polar extracts. Water, ethanol, methanol, acetone, chloroform and hexane are
some of the common solvents used for extracting bioactive compounds and to
determine antibacterial activity from plants (Cowan, 1999). These extracts are complex
containing hundreds of different compounds and the isolation of a single bioactive
compound is difficult. Except for water, all the other solvents are antimicrobial agents.
However, Kotzé and Eloff (2002) showed that the effect of the extractant on subsequent
separation procedure is not important, but the extractant should not inhibit the bioassay.
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