Anti-inflammatory efficiency of Lac extracts

Abstract

Lac extracts such as lac dye, seed lac and shellac, have been used in various important industries including pharmaceuticals. However, they have rarely been reported of their biological activities. Many tropical and internal products have been developed without investigation on significant activities such as anti-inflammation and antimicrobe. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) are key enzymes in inflammatory mechanism which cause inflammation, pain, fever, cancer, and rheumatoid arthritis. In this study, lac products including lac dye, seed lac and dewaxed shellac, from rain trees (Samanea saman Merr.) and lychee trees (Litchi chinensis Sonn.) were extracted by water and alcoholic extractions. Then, lac products and their active components were investigated on anti-inflammatory activity monitoring gene and protein expression using real-time quantitative reverse transciiption-polymerase chain reaction (qRT-PCR) and western blot, respectively. Furthermore, the lac products and their bioactive components were examined on the antimicrobial activity using agar well diffusion and pour plate method, the clear zones of Escherichia coli and Staphylococcus aureus on the agar were observed. The bioactive components were analyzed by thin-layer chromatography (TLC) with laccaic acid (natural red 25) and aleuritic acid as authentic samples. The results showed that laccaic acid (natural red 25) and aleuritic acid were major active components of lac dye and resinous lac products, seed lac and dewaxed shellac, respectively. The concentrations range from 1- 1,000 µM of active compounds, 1-500 µg/mL of lac dye and 1-25 µg/mL of resinous lac products were nontoxic to cells which exhibited over seventy percent cell viability. The involving inflammatory gene expressions were reduced dramatically in dose dependent manner. The resinous lac products significantly inhibited Escherichia coli and Staphylococcus aureus proliferation. Our study showed the efficacy of lac products and their bioactive compounds on anti-inflammation