Chitin was synthesized from Nigerian brown shrimps by a chemical process involving demineralization and deproteinisation. Deacetylation of the chitin was conducted to obtain Chitosan. The chitin and chitosan were characterized using FTIR, XRD and SEM. Proximate and elemental analysis were also conducted. The percentage yield of chitin was 8.9%. The degree of deacetylation of chitin was found to be 50.64% which was a low value compared to previous works and can be attributed to the low alkali concentration and heating time. XRD patterns indicated that chitin was more crystalline than the corresponding chitosan. FTIR spectra indicated the presence of functional groups associated with different bands, the intensities and stretching established that the samples are chitin and chitosan. SEM analysis also indicated morphological differences between the chitin and chitosan.

The in vitro antimicrobial activities of the whole plant extract (ethanolic-CEE) of Chrozophora senegalensis and its fractions (ethyl acetate-EAA, n-butanol-NBE, aqueous-AQE) were assayed using the agar plate diffusion and nutrient broth dilution methods. Test microorganisms were Bacillus subtilis (NCTC 8326 B76), Escherichia coli (ATCC 11775), Pseudomonas aeruginosa (ATCC 10145), Staphylococcus aureus (ATCC 021001). Aspergillus flavus, Aspergillus niger, Candida albicans and Salmonella typhi -laboratory isolates. CEE, EAA and NBE inhibited all the test bacterial organisms and a fungus-Aspergillus flavus. AQE inhibited only Salmonella typhi and Bacillus subtilis. None of the extracts had activity on other 3 fungal organisms tested. CEE and EAA showed minimum inhibition concentration (MIC) of 0.390 and 3.125 mg/ml against S. typhi and E. coli, while NBE and AQE had MIC of 3.125 and 1.563 mg/ml against S. typhi respectively. NBE had an MIC of 12.500 mg/ml against E. coli. The minimum bactericidal concentration (MBC) of CEE and EAA was found to be <0.098 against S. typhi. The MBC of AQE was 12.5 mg/ml against E. coli and S. aureus, and 6.25 mg/ml towards P. aeruginosa. CEE and EAA exhibited similar antibacterial activities, followed by AQE. The extracts revealed the presence of carbohydrates, tannins, saponins, sterols determined by utilizing standard methods of analysis. This study has justified the traditional use of the plant for treating diarrhea, boils and syphilis.

The efficacy of methanolic seed extracts of Amomum subulatum Roxb. activity against bacterias such Staphylococcus aureus, Streptococcus pneumoniae, Bacillus subtilis, Salmonella typhi, Klebsiella pneumoniae, Pseudomonas aerugenosa and Candida albican senegalensis was studied. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts was determined using standard methods. Results obtained showed considerable inhibition against the bacteria tested except Salmonella pyrogenes and Escheria Coli which showed considerable resistance at all concentrations of the extract. It can also observe that the extract exhibited greater inhibition on Klebsiella pneumonia and Pseudomonas aerugenosa (18±0.2 and 17±0.3). However the standard antibacterial drug tetracycline exhibit superior activity than the extract. Both the MICs and MBCs of the extract ranges from 50 to 200 mg/ml. Its further reveals that Bacillus subtilis, Klebsiella pneumonia and Staphylococcus aureus exhibit broadest activity at MIC and MBC concentrations of 50mg/ml. While the rest Salmonella typhii and Pseudomonas aerogunosa and candida albicans of the bacteria shows negative turbidity and resistance at MIC and MBC of 100mg/ml. This activity was indicative of the possible means of finding pure active principles from natural source with possible high potency that could serve as a lead to the pharmaceuticals. The low concentration (MIC and MBC) activity of the methanolic extracts give credence and scientific base for the claim therapeutic capabilities of Amomum subulatum as an anti-bacterial agent. The extract concentrate yield of the methanolic extracts was estimated to be 9.8%w/w which is brown in colour and oily in texture. Preliminary screening analysis of the powdered methanolic seed extracts showed the presence of Carbohydrate, tannins, cardioactive glycosides, tepenes, flavonoids, alkaloids and saponins. Anthraquinone was not found in the extract. The study provides the basis of use of this plant Amomum subulam in treatment of infections caused by pathogens (bacteria) and the phytochemical found are implicated in having anti-bacterial properties.

Waltheria indica showed phytochemicals like cardenolides, cardiac glycosides, flavonoids, saponins, tannins, and terpenoids. However, alkaloids were found in only W. indica. The extracts showed dose-dependent broad spectrum antimicrobial activities against the test microorganisms which could be attributed to the secondary metabolites present. Hence both plants might be used as a natural source for preparation of new drugs.

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