Secondary Metabolites

Turmeric belongs to the family of Zingiberaceae and natively grown in India and Southeast Asia.Turmeric plant contains rhizome which has several secondary metabolites including steroids, curcuminiods and sesquiterpenes with cucurmin being the principal component of the yellow pigment and the major bioactive substance curcumin. Enteric bacteria are Gram negative bacteria
found in the human and animal intestine.Examples are Shigella sp, Salmonella sp and Eschericha coli. Antibacterial property of turmeric requires the use of its rhizomes. The rhizomes were shade dried and grounded to powder.90g of the sample was measured and mixed with 150ml ethanol (ethanol extract), while 150g of powdered sample was mixed with 270ml of water (aqueous extract). Using Muller Hinton agar, cultures of test bacteria were swabbed on the Muller Hinton agar plates, a hole was drilled at the middle of the culture and then 0.01ml of the extracts was poured into the hole.The culture was incubated at 370C for 24 hours in an upright position. Results from both extracts (aqueous and ethanol) on test bacteria (Eschericha coli, Salmonella sp and Shigella sp) showed that turmeric has antibacterial property because it was able to Inhibit the growth of test bacteria. Ethanolic extract of turmeric (curcumin) showed more effects on enteric bacteria and it's because the ethanol helps to boost the antibacterial activities of turmeric than aqueous extract. Phytochemical screening was carried out on turmeric and it shows the presence of saponin, tannin, alkaloid, flavonoid and steroid chemical compound. The presence of curcumin inhibit the growth of enteric bacteria such as Eschericha coli, Salmonellasp and Shigella sp. Curcumin posses invitro antimicrobial potential against a wide range of microorganisms. Curcumin possesses a synergistic effect with important antibiotics such as cefixime, vancomycin and tetracycline against enteric bacteria. Turmeric destroys the bacteria cell membrane through penetration and therefore distortion of the cell shape happens as a result of exposure to curcumin. Thus, the damage of the cell membrane is the key mechanism of curcumin in enteric bacteria.

Soil actinomycetes are recognized as promising sources of new antimicrobials. Antimicrobial resistance in pathogens has greatly increased in recent years, and has become a global public health problem. New antimicrobials are continuously required to combat these resistant strains. The aim of this study was to isolate and screen soil actinomycetes and evaluate their secondary metabolites for antimicrobial activities against selected pathogenic bacteria and fungi. Four soil samples were collected, pre-treated with CaCO3, serially diluted and spread plated on actinomycetes isolation agar (AIA) and international streptomyces project media 2 (ISP-2), supplemented with nystatin, neomycin and polymyxin B . Perpendicular streak method was used to check antagonistic activities of the isolated actinomycetes against test microorganisms. Small scale submerged fermentation system was used for the production of antimicrobial metabolites from the isolates. Agar well diffusion was then used to evaluate antimicrobial activities of the crude extracts against the test microorganisms. The average aerobic actinomycetes plate count from the different soil samples ranged from 3.0×10 4 ± 2.4 to 3.6×10 4 ± 1.9 CFU/g. A total of 28 different microorganisms were isolated, characterized by cultural and morphological methods and identified as actinomycetes. Out of the 28 isolates, 10 (36%) showed antimicrobial activities on primary screening; from which isolates BYQ3, CYP1, CYP2, CYP4 and CYQ2 were selected for their wide spectrum of activities. Diameters of inhibition zones produced by these 5 isolates against the test microorganisms on secondary screening, ranged from 0 to 26 mm. Isolates CYP1 and CYP2 had the widest zones with CYP1 producing 26 mm against Candida albicans. The two promising isolates were further characterized by physiological and biochemical tests and identified as genus Streptomyces. Isolate CYP1 was then identified to the specie level by 16S rRNA gene sequence analysis which confirmed that Streptomyces sp. CYP1 was homologous to Streptomyces albus (strain DSM 40313) of the order Actinomycetales and class Actinobacteria. Optimization of production conditions, further purification, structural elucidation and characterization are recommended to know the quality, novelty and commercial value of these antimicrobials key words