Antifungal Activities of Origanum Oil Against Candida Albicans
Essential Oils Enhance Insulin Sensitivity and Lower Blood Pressure in Zucker Fatty Rats
Anti Bacterial Effects of the Edible Oil of Oregano Against Staphylococcus Aureus
Antifungal activities of origanum oil against Candida albicans
The antimicrobial properties of volatile aromatic oils from medicinal as well as other edible plants has been recognized since antiquity. Origanum oil, which is used as a food flavoring agent, possesses a broad spectrum of in vitro antimicrobial activities attributed to the high content of phenolic derivatives such as carvacrol and thymol. In the present study, antifungal properties of origanum oil were examined both in vitro and in vivo. Using Candida albicans in broth cultures and a micro dilution method, comparative efficacy of origanum oil, carvacrol, nystatin and amphotericin B were examined in vitro. Origanum oil at 0.25 mg/ml was found to completely inhibit growth of C. albicans in culture. Growth inhibitions of 75% and >50% were observed at 0.125 mg/ml and 0.0625 mg/ml level, respectively. In addition, both the germination and the mycelial growth of C. albicans were found to be inhibited by origanum oil and carvacrol in a dose-dependent manner. Furthermore, the therapeutic efficacy of origanum oil was examined in an experimental murine systemic candidiasis model. Groups of mice infected with C. albicans were fed varying amounts of origanum oil in a final volume of 0.1 ml of olive oil. The daily administration of 8.6 mg of origanum oil in 100 microliters of olive oil/kg body weight for 30 days resulted in 80% survivability, with no renal burden of C. albicans as opposed to the group of mice fed olive oil alon, who died within 10 days. Similar results were obtained with carvacrol. The results from our study encourage examination of the efficacy of origanum oil in other forms of systemic and superficial fungal infections and exploration of its broad spectrum effect again other pathogenic manifestations including malignancy.
Received 27 June 2001; accepted 14 September 2001.
[printed in Molecular and Cellular Biochemistry B228: 111-117, 2001. copyright 2001. Kluwer Academic Publishers.]
Essential oils enhance insulin sensitivity and lower blood pressure in Zucker Fatty Rats
The incidence of insulin resistance (IR), even type 2 Diabetes Mellitus (DM2), is increasing rapidly in the USA, probably due to dietary indiscretions. Since many drugs developed to treat DM2 have been associated with significant adverse , it is important to examine the potential of safe-proven natural products to enhance insulin sensitivity. Although the antibacterial/antifungal activities of essential oils (EO) such as oregano and cumin are recognized by some, their effects on insulin sensitivity have not been investigated extensively. Since Zucker Fatty Rats (ZFR) are an animal model of peripheral IR and show many of the characteristics of DM2, we examined the effects of a combination of EO (fenugreek, cumin, pumpkin seed, and oregano) 25% v/v in olive oil, designated here as EO1, on ZFR. A single dose of EO1 decreased systolic BP from baseline at 4h (163+/-6 vs. 143+/-8 mm Hg) in 6 ZFR. This significant decrease of approximately 20 mm Hg decreased remained over the 3 weeks of the study, but BP returned to baseline 30 days after discontinuation of EO1. on EO1, fasting glucose levels were significantly lower than control (183+/-4.1 vs. 231+/-13.5 mg/cl). With a glucose challenge, circulating glucose concentration in EO receiving ZFR were significantly lower than control at 2 and 3 h (66-75% of baseline). Circulating insulin levels remained lower in EO1 rats throughout the challenge (75-82% compared to baseline), but the differences did not reach statistical significance. Circulating levels of cholesterol and triglycerides were not different over the 3 weeks of the study. These same oils given to genetically hypertensive rats (SHR) produced similar but less dramatic decreases in BP and triglyceride levels. Our results suggest that various EO improve insulin sensitivity in ZFR and along with their antigermicidal effects may be important in the treatment of IR or DM2 and the associated BP elevations. Other combinations of EO are being compared to the original EO1 for their anti diabetic and anti hypertensive potential.
From the American College of Nutrition 42nd Annual Meeting Orlando, FL October 3-7, 2001. Session A: Endocrinology/Cardiovascular/Gastroenterology/Immunology.
Anti Bacterial effects of the edible oil of oregano against Staphylococcus Aureus
The antimicrobial properties of volatile aromatic oils from edible plants has been recognized since antiquity. Origanum oil, used as food flavoring agent, has been claimed to possess a broad spectrum of antimicrobial activity due to its high content of phenoic derivatives such as Carvacrol, Thymol, etc. Recently we demonstrated the antifungal properties of Origanum oil against Candida Albicans both in vitro and in vivo. Using S. aureus in broth cultures and a micro dilution method, comparative efficacy of Origanum oil, Streptomycin, Penicillin and Vanomycin were examined in vitro. Origanum oil at 0.25% mg/ml was found to completely inhibit the growth of S. aureus in culture. A 75% and >50% growth inhibition was observed at 0.125 mg/ml and 0.0625% mg/ml level. The in vivo therapeutic efficacy of the edible Origanum oil and one of its major constitient, Carvacrol, were examined in a murine systemic bacterimia model. Groups of mice infected with S. aureus were gavaged with varying amount of Origanum oil or, Carvacrol in a final volume of 0.2 ml of Olive oil. A dose dependent survival was observed among mice receiving Origanum oil. A 50% of mice receiving Origanum oil and Vancomycin, for 30 days survived, compared to the mice that received Olive oil alone, who died within 3 days. Although a similar dose dependent prolong survival was observed among mice receiving carrying amounts of Carvacrol in olive oil, none survived beyond 21 days. Results from the experiments to determine the exact dose of the Origanum oil required for a 100% survival with the complete elimination of the renal burden of S. aureus at the end of 30 days will also be presented. Our study demonstrates both the in vitro bactericidal and the in vivo therapeutic efficacy of the natural Origanum oil in systemic bacterimis due to S. aureus.
From the American College of Nutrition 42nd Annual Meeting Orlando, FL October 3-7, 2001. Session D: Dietary Supplements/Nutraceuticals and Functional Foods.