الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 161 |  |  |
| | | from | 161 | | |
Abstract
Microbiological studies on the contamination of certain cosmetic products by microorganisms
Preservation of cosmetic products by natural antimicrobial compounds as alternatives of chemosynthetic preservatives is one of the most important goals that the modern sciences are focused. Also, the use of natural antimicrobial compounds has the advantage of being more acceptable to the consumers as these are considered as non chemical. In addition, a large number of medicinal plant’s constituents have been investigated for their antimicrobial properties against some bacteria and fungi.
Therefore, our study aim to evaluate the efficiency of some essential medicinal plant oils as natural preservatives for cosmetic products. For this purpose, a series of laboratory experiments was designed and carried out. Obtained results could be summarized in the following:
Screening of cosmetic samples for total microbial count
)A) Out of 140 cosmetic samples collected from Cosmetic lab. National Organization for Drugs Control and Research (NODCAR), Egypt, and screened for their contamination with microorganisms, only 32 samples (22.68(% were contaminated with bacteria or fungi or both. Maximum bacterial counts were observed in shampoo samples compared to other tested cosmetic samples, followed by gel, solution, cream and oil samples. Total bacterial, yeast and mold counts in shampoo, gel, solution, cream and oil samples varied.
(B) The maximum total bacterial counts were observed in shampoo-3 followed by shampoo-129, shampoo-13, shampoo-134, shampoo-9, cosmetic gel-68, shampoo-130, shampoo-131 and cos-sol-28. While, maximum total molds and yeast counts were observed in cosmetic gel-68 followed by cos-sol-28, shampoo-130. shampoo-3, shampoo-13 and shampoo-131. In contrast, molds and yeast were not detected in shampoo-9, shampoo-129 and shampoo-134.
According to the abovementioned results, shampoo-3, shampoo-9, shampoo-13, shampoo-129. shampoo-130, shampoo-134, shampoo-131, cosmetic gel-68 and cos-sol-28 were selected for subsequent studies.
Detection of pathogens in selected cosmetic samples
Detection of pathogens in selected cosmetic samples was reported according to the method described by Tirumalai (2007a&b)
Results revealed that shampoo-9, shampoo-131 and cos.gel-68 were contaminated with E. coli. while, shampoo-3, shampoo-13, shampoo-129 and cos.sol-28 samples were contaminated with Staphylococcus aureus. Shampoo-130 and shampoo-134 samples were contaminated with Pseudomonas aeruginosa. On the contrary, the detection of Salmonella sp. in tested cosmetic samples was negative. The pathogenic bacteria which isolated from cosmetic samples were used in the subsequent studies.
Antimicrobial activities of various medicinal plant oils against pathogenic bacteria isolated from cosmetic samples
Antibacterial activity of some medicinal plant oils ((lemon grass, cumin, peppermint, chamomile, thyme, wheat germ and green tea) against pathogenic bacteria isolated from tested cosmetic samples were studied. Results revealed that:
(A) All the tested medicinal plant oils, except green tea and wheat germ oils, had broad spectrum of antibacterial activity against the various tested pathogenic bacteria.
(B)The maximum antibacterial activity was observed with lemon grass oil compared to oils, which gave 30 mm inhibition zone followed by cumin, peppermint, chamomile, thyme and wheat germ oil.
)C) The maximum antibacterial activity of lemon grass oil (0.25 nig/ml) was observed against E. coli-9 which gave 30 mm inhibition zone followed by Ps. aeruginosa-130, Staph. aureus-3, E. coli -131, Staph. aureus -13, Staph. aureus-129, Ps. aeruginosa-134, Staph, aureus-28 and E. coli -68.
(D) The maximum antibacterial activity of cumin oil (0.25 mg/ml) was observed against E. coli -9 which gave 28 mm inhibition zone followed by Staph. aureus-129, Staph, aureus-2%, Ps. aeruginosa-130, E. coli-131, Ps. aeruginosa-134, Staph, aureus-13, E. coli-68 and Staph, aureus-3 .
(E) The maximum antibacterial activity of peppermint oil (0.25 mg/ml) was observed against E. coli -9 which gave 25 mm inhibition zone followed by Staph. aureus-3. Staph, aureus-129, Staph, aureus-13, Staph, aureus-28, E. coli-131, Ps. aeruginosa-130, E. coli-68 and Ps. aeruginosa-134.
(F) The maximum antibacterial activity of chamomile oil (0.25 mg/ml) was observed against E. coli-131 which gave 20 mm inhibition zone followed by Staph. aureus-13, Ps. aeruginosa-134, Staph. aureus-3, E. coli-9, E. coli-68, Staph. aureus-129, Staph. aureus-28 and Ps. aeruginosa-130 .
)G) The maximum antibacterial activity of thyme oil (0.25 mg/ml) was observed against Ps. aeruginosa-130 which gave 17 mm inhibition zone followed by Staph. aureus-134, Staph. aureus-13, E. coli-131. E. coli-9, Staph. aureus-129, E. coli-131, E. coli-9 and Staph. aureus-3.
(H) The maximum antibacterial activity of wheat germ oil (1.0 mg/ml) was observed against Staph. aureus-13 which gave 13 mm inhibition zone followed by Staph. aureus-28, Ps. aeruginosa-134 and E. coli-68.
On the light of the abovementioned results, lemon grass, cumin, peppermint, chamomile, thyme oils were selected for the subsequent studies.
Challenge test of selected medicinal plant oils against microbial contamination of tested cosmetic samples
The effect of medicinal plant oil additions (0.25, 0.5 and 1.0 mg/ml) to cosmetic samples against microbial contamination of cosmetic samples was studied. Results show that:
)A) Separately additions of all the tested medicinal plants oils to tested cosmetic samples caused a dramatic decreases in total microbial counts. Pathogenic bacteria not detected after the incubation periods (7, 14 & 21 days) at 37±2 °C. In addition, the rate of microbial count decreasing was influenced by the type and concentration of tested medicinal plant oil.
)B) Total yeasts and molds counts of the various tested cosmetic samples which treated with the various medicinal plant oils and incubated for 21 days at 37±2 °C decreased to less than 5 cfu/g.
Effect of oils additions on microbial contamination of cosmetic samples
from obtained data for each tested medicinal plant oil we can summerized that 0.25% oils decreased greatly total bacterial counts (TBC). Further concentrations of oils (0.5% and 1%) caused slight decrease for TBC. Incubation of the product for 7 days in the presence of 0.25% thyme oil was sufficient to reduce the TBC of the products to meet the requirements (<100 cfu/ml or gm) according to the united states pharmacopeia. Further incubation periods caused slight decrease for TBC.
Evaluation of tested medicinal plant oils efficiency against microbial contamination of each cosmetic sample.
This part of study aimed to detect the most efficient medicinal plant oil as a natural preservative for each tested cosmetic sample. Results appeared that:
(1) lemon grass oil was the most efficient medicinal plant oil against microbial contamination of shampoo-3, shampoo-9, shampoo-129 and cos-gel 86 samples, followed by cumin oil.
(2) Cumin oil was the most efficient oil against microbial contamination of shampoo-129 and cos-solution 28 samples, followed by lemon grass oil.
(3) Peppermint oil and chamomile oil were the most efficient oils against microbial contamination of shampoo-130 and shampoo-134 samples, respectively, followed by lemon grass for both tested cosmetic samples.
On the light of the abovementioned results, it could be concluded that using of tested medicinal plants oils (Lemon grass cumin, peppermint, chamomile and thyme) as natural preservatives markedly contributed in decreasing of microbial contamination of cosmetic products, instead of chemosynthetic preservatives which have harmful side effects on human body.