Phytosterol, Lipid and Phenolic Composition, and Biological Activities of Guava Seed Oil.

Plant seeds have been found to contain bioactive compounds that have potential nutraceutical benefits. Guava seeds (Psidium guajava) are by-products in the beverage and juice industry; however, they can be utilized for a variety of commercial purposes. This study was designed to analyze the phytochemicals of the n-hexane extract of guava seed oil (GSO), to study its free-radical scavenging activity, and to monitor the changes in serum lipids and fatty acid profiles in rats that were fed GSO. The GSO was analyzed for phytochemicals using chromatographic methods. It was also tested for free-radical scavenging activity in hepatoma and neuroblastoma cells, and analyzed in terms of serum lipids and fatty acids. GSO was found to contain phenolic compounds (e.g., chlorogenic acid and its derivatives) and phytosterols (e.g., stimasterol, ß-sitosterol and campesterol), and exerted radical-scavenging activity in cell cultures in a concentration-dependent manner. Long-term consumption of GSO did not increase cholesterol and triglyceride levels in rat serum, but it tended to decrease serum fatty acid levels in a concentration-dependent manner. This is the first study to report on the lipid, phytosterol and phenolic compositions, antioxidant activity, and the hepato- and neuro-protection of hydrogen peroxide-induced oxidative stress levels in the GSO extract.

Linoleic acid-rich guava seed oil: Safety and bioactivity.

Guava (Psidium guajava) is a widely consumed fruit and has been commercialized in markets. The seeds are by-products of the processing procedures performed by the commercial guava juice industry. They are considered a nutritional resource that has been poorly utilized as they contain essential fatty acids such as linoleic acid (LA) and phenolics in abundance. In the study, guava seed oil (GSO) was used, which was obtained by hexane extraction of guava seeds to determine composition and test toxicity, cell migration, cancer cell viability, and plasmodium growth. GSO was found to be relatively nontoxic to normal hepatocytes and peripheral blood mononuclear cells, with mice for 14 days showing median lethal dose (LD50 ) > 10 mg/kg and rats for up to 90 days. Surprisingly, the oil inhibited the proliferation of the human erythroleukemic cells in a dose-dependent manner with the half maximal inhibitory concentration values of 155 and 137 µg/ml at 24 and 48 hr, respectively. Importantly, GSO at 500 µg/ml was found to increase the degree of migration of keratinocytes (HaCaT). These observations suggest that edible P. guajava seed oil, which is abundant with linoleic acid and antioxidants, can promote skin wound healing and inhibit the proliferation of leukemic cells.