Preventive effects of tamarind seed coat extract on UVA-induced alterations in human skin fibroblasts.

One of the most damaging actions on skin is from solar radiation, particularly from its ultraviolet (UV) component, through the formation of oxidative species. Thus, an antioxidant strategy that prevents the formation of these oxidants could form the basis of an efficacious cutaneous protectant. Many herbal materials contain antioxidant polyphenols, and this study assessed the possibility that tamarind seed coat extract could fulfill this role. An alcoholic extract of the tamarind (Tamarindus indica L.) seed coat showed stronger antioxidant activity (2,2-diphenyl-1-picrylhydrazyl inhibition, EC(50) = 12.9 µg/ml) than L-ascorbic acid (EC(50) = 22.9 µg/ml) and α-tocopherol (EC(50) = 29.3 µg/ml). In cultured fibroblasts taken from human skin, hydrogen peroxide (100-1000 µM) damaged 62-92% of the cells compared to only 35-47% when the cells were preincubated in extract (200 µg/ml) for 24 h. UVA (40 J/cm2) irradiation of human fibroblasts damaged 25% of the cells but the death rate was reduced to 10% with extract. UV irradiation increased the proportion of cells arrest in G(0)/G(1) phase (from 59% to 78%) but this was largely prevented by the extract (64%), according to flow cytometry. Intracellular total glutathione of UVA-irradiated cells pretreated with the extract increased to 10-25% compared to the non-pretreated group at 24-72 h after irradiation. Fibroblasts typically increased matrix metalloproteinase-1 secretion after photodamage, and this is prevented by the extract. This is the first report showing that tamarind seed coat extract is an antioxidant and can protect human skin fibroblasts from cellular damage produced by UVA and thus may form the foundation for an antiaging cosmetic.

Solid-phase preparation of protein complexes.

Protein-protein conjugation is usually achieved by solution phase methods requiring concentrated protein solution and post-synthetic purification steps. In this report we describe a novel continuous-flow solid-phase approach enabling the assembly of protein complexes minimizing the amount of material needed and allowing the repeated use of the same solid phase. The method exploits an immunoaffinity matrix as solid support; the matrix reversibly binds the first of the complex components while the other components are sequentially introduced, thus allowing the complex to grow while immobilized. The tethering technique employed relies on the use of the very mild synthetic conditions and fast association rates allowed by the avidin-biotin system. At the end of the assembly, the immobilized complexes can be removed from the solid support and recovered by lowering the pH of the medium. Under the conditions used for the sequential complexation and recovery, the solid phase was not damaged or irreversibly modified and could be reused without loss of binding capacity. The method was specifically designed to prepare protein complexes to be used in immunometric methods of analysis, where the immunoreactivity of each component needs to be preserved. The approach was successfully exploited for the preparation of two different immunoaffinity reagents with immunoreactivity mimicking native squamous cell carcinoma antigen-immunoglobulin M (SCCA-IgM) and alphafetoprotein-immunoglobulin M (AFP-IgM) immune complexes, which were characterized by dedicated sandwich enzyme-linked immunosorbent assay (ELISA) and immunoblot. Besides the specific application described in the paper, the method is sufficiently general to be used for the preparation of a broad range of protein assemblies.

Anti-inflammatory, analgesic and wound healing activities of the leaves of Memecylon edule Roxb.

AIM OF THE STUDY: To determine the anti-inflammatory, analgesic and antioxidant activities of the leaves of Memecylon edule Roxb. used traditionally in Thailand. MATERIALS AND METHODS: Hexane, (Hex), ethyl acetate (EtOAc), methanol (MeOH) and 50% methanol (MeOH50) fractions of the dry leaves were tested in vitro for their interleukin-10 production; the most active fraction was further studied in vivo for its anti-inflammatory and analgesic activities using the ethylphenylpropiolate (EPP)-induced mouse ear edema and the writhing test with mice. All fractions except Hex were tested for their radical scavenging activity towards 1'-diphenyl-2-picrylhydrazyl radical (DPPH). RESULTS: The EtOAc showed the highest stimulation for interleukin-10 production. In the EPP test, this fraction was significantly active 30 min after topical application at all doses used (0.5, 1.0, 2.0mg/ear); after 4h and at 1.0mg/ear EtOAc was slightly less active (inhibition 47.8%) than the reference, indomethacin, at the same dose (62.4%). At 200mg/kg orally, the EtOAc caused a significant inhibition of the writhing response by 56.6% which was like indomethacin at 10mg/kg. EtOAc, MeOH and MeOH50 exhibited radical scavenging activity. The order of IC(50) values was: ascorbic acid (9.1 microg/mL)>trolox (11.6 microg/mL)>MeOH (46.9 microg/mL)>MeOH50 (152.1 microg/mL)>EtOAc (1742.2 microg/mL). CONCLUSION: The results provide support for the traditional use of Memecylon edule leaves in relieving inflammation and pain.