Boswellia serrata, also known as frankincense, has a long history of use as an anti-inflammatory in Ayurvedic medicine.
The gum resin of the plant contains boswellic acids. Of these, acetyl-keto-beta (AKBA) is understood to be the most potent inhibitor of inflammation mediators.
5-Loxin is standardised to 30 percent AKBA - said the be the highest concentration commercially available.
5-Loxin was launched to market in late 2004, and was the first product to come out of PLT's formal alliance with Indian herbal extracts specialist Laila Nutraceuticals. It is available in a number of products, including supplements by Life Extension Foundation and Nature's Plus.
PLT's Eric Anderson told NutraIngredients-USA.com that 5-Loxin "is doing extremely well in the U.S. market, with international expansion planned".
The new study was conducted by scientists at the Laila Research Center in India and Creighton University Medical Center, Omaha, NE, and published in the April issue of Toxicology Mechanisms and Methods.
Paul Flowerman, president of PLT, said: "This is an important study affirming 5-Loxin's safety in several models."
The scientists conducted acute oral, acute dermal, primary skin and eye irritation, and dose-dependent 90-day subchronic toxicity studies. In a rat model, they determined that the acute oral LD50 (lethal dose for 50 percent of subjects) was greater than 5,000 mg/kg in both males and females.
Necropsy revealed no changes in body weight or other adverse effects.
In primary skin irritation test on rabbits, 5-Loxin was classified as non-irritating, and only mildly irritating to the eye. Acute dermal LD50 was found to be greater than 2000 mg/kg.
A dose-dependent 90-day subchronic toxicity study demonstrated no significant changes in selected organ weights individually and as percentages of body and brain weights.
Supplementation seen to cause changes in hepatic DNA fragmentation on 30, 60, or 90 days of treatment, and hematology, clinical chemistry, and histopathological evaluations did not show up adverse effects in any of the organs tested.
"Taken together, these results demonstrate the broad spectrum safety of 5-Loxin," wrote the researchers.
The safety study comes on the back of previously published in vivo and in vitro efficacy studies.
In particular, a study published April 2005 issue of DNA and Cell Biology identified its anti-inflammatory and collagen-sparing mechanisms and demonstrating in vivo effects similar to those produced by ibuprofen.
5-Loxin was shown to inhibit expression of matrix metalloproteinase enzymes, which selectively destroy peptide bonds, collagen and cartilage. It was also seen to inhibit the adhesion molecules ICAM and VCAM which cause pain and swelling by drawing white blood cells to the inflamed area - an effect with PL Thomas called "striking".
5-Loxin follows a different inflammation pathway to that of COX-2 inhibitors. It is a selective, non-redox inhibitor of the enzyme 5-lipoxygenase, which means it does not interact with other redox systems, leading to side effects.
Anderson said that the alliance with Laila is expected to bear more fruit soon:"Currently we have a number of very interesting technologies in our 'incubator' and we look forward to introducing these products to the nutraceutical marketplace in the near future."