Report of antimicrobial activity are also there from stem, bark and root of Rhizophora apiculata (Lim et al., 2006), Olax subscorpioidea, (Ayandele and Adebiyi, 2007), Cylicodiscus gabunensis (Kouitcheu et al., 2007), Jatropha curcas (Igbinosa et al. 2009), Tectona grandis (Krishna and Nair, 2010), Bridelia micrantha (Adefuye et al., 2011), Alafia barteri (Hamid and Aiyelaagbe 2011), Garcinia kola (Ogunjobi and Ogunjobi 2011), against bacteria such as Streptococcus mutans, Klebsiella pneumonia, Shigella dysenteriae, Staphylococcus aureus, Salmonella typhimurium. Pine needle extract have also been showed to have antifungal effect against Alternaria mali having MIC in the range of 0.1 mg/ml- 45mg/ml (inhibition zone 7.2mm-21.5mm). Calotropis procera (Mako et al., 2012) a flowering plant, Tinospora crispa (Mohammed, 2012) a medicinal plant its leaves and roots showed antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogen, Escherichia coli and Candida albicans. Sumthong (2007) reported that saw dust of the tropical hardwoods Tectona grandis, Xylia xylocarpa, Shorea obtusa, Shorea albida and Hopea odorata had activity against Aspergillus niger with effective dose of 25 ppm. Wastes from food industry, large fruit and vegetable distribution centres such as garlic stalk juice, olive mill, beet stalk, peanut peel and guava bagasse showed inhibitory effect against bacteria with MIC in the range between 0.78mg/ml-25mg/ml .Trapa natans a household waste was found inhibitory to Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli (Cekmez, 2010; Martin et al., 2012).
2.2 EXTRACTION, PURIFICATION AND CHARACTERIZATION OF THE BIOACTIVE COMPOUND:
SOLVENT EXTRACTION
Considering the importance of the healing property of the bioactive compounds it has become a necessity to build up a standard towards an integrated approach to extract, purify and characterize active compounds and ultimately to test biological activity of the active compound.
The extraction of bioactive compounds from plant materials is the first step in the utilization of phytochemicals in the preparation of dietary supplements or nutraceuticals, food ingredients, pharmaceutical and cosmetic products. Bioactive compounds can be extracted from fresh, frozen or dried plant samples. Usually before extraction plant samples are treated by milling, grinding and homogenization, which may be preceded by air-drying or freeze-drying. Generally, freezedrying retains higher levels of bioactive content in M.oleifera and J. curcas samples than air-drying . However, air-dying , freeze-drying, can cause undesirable effects on the constituent profiles of M.oleifera and J. curcas samples, therefore care should be taken while implementing these processes. Solvent extractions are the most commonly used procedures to prepare extracts from M.oleifera and J. curcas materials due to their ease of use, efficiency, and wide applicability. The yield of chemical extraction depends on the type of solvents with varying polarities, extraction time and temperature, sample-to-solvent ratio as well as on the chemical composition and physical characteristics of the samples. Active compounds in M.oleifera and J. curcas may be present in different states for example phenolics may exist in simple state as phenolic acids or anthocyanins to highly polymerized substances as tannins, in different quantities. Moreover, phenolics may also be associated with other plant components such as carbohydrates, proteins, organic acids and fats. As a result, additional steps may be required to remove those unwanted components. Therefore, there is no universal extraction procedure suitable for extraction of any bioactive molecule.
