234 JOURNAL OF COSMETIC SCIENCE due to its best taste as compared to that of other fruits. Generally, GM is a tropical fruit, predominantly found in Southeast Asia. It has been used in traditional medicine for the treatment of diarrhea, skin infections, wounds, and chronic ulcers, as well as an astrin­ gent. Several studies have revealed that GM extracts exhibit antimicrobial (1), antipro­ liferative (2,3), antioxidant (4-6), and anti-inflammatory (7-10) properties. The pericarp of GM was reported to be a good source of mangostin, xanthone, chrysanthemin, garcinone, tannin, gartanin, vitamins Bl, B2, and C, and other bioactive substances (11). Because of the antioxidant activity of GM extracts, they can be used as ingredients in many cosmetic applications, such as medicated soaps and anti-aging products. Their antibacterial properties also make them suitable for anti-acne products. They also tighten the skin, which, when combined with the anti-oxidant properties, makes them ideal for the development of anti-aging skin-care products. Some GM extracts are also suitable as food supplements and beverages. In recent years, the electrospinning process has attracted a great deal of attention due to its ability to produce ultrafine fibers with diameters in the range of nanometers to sub-micrometers that exhibit high surface-area-to-volume or mass ratios (12,13). The principle of this process is the use of electrostatic force as the main driving force for fiber formation (14-16). The morphology of the electrospun fibers depends on a number of parameters, such as solution concentration, solution conductivity, applied electric field, collection distance, and collection time (15, 1 7). Electrospun polymeric fibers have a wide range of medicinal applications, such as immobilization of enzymes (18), tissue engineering scaffolds (19,20), and drug delivery systems (21-24). One of the obvious advantages of the electrospinning process over the conventional film-casting technique is the highly porous nature of the electrospun fiber mats that exhibit much greater surface area, assumingly allowing drug molecules to diffuse out from the matrix much more conveniently. In this study, poly(vinyl alcohol) (PVA), one of the most popular hydrogel polymers, was chosen as the matrix material. This is due to its hydrophilicity, good chemical stability, and good thermal stability (25). PVA is also widely used as a controlled-releasing carrier of drugs and proteins because of its good tissue compatibility, ease of manipulation under swelling conditions, solute permeability, and, particularly, excellent electrospin­ nability (26). Various parameters affecting the morphology of electrospun PVA fibers, e.g., solution concentration, solution flow rate, degree of hydrolysis, applied electrical potential, collection distance, ionic salt addition, PV A molecular weight (26), and pH (27) have been investigated. In the present study, mats of PVA nanofibers were prepared by electrospinning, and these electrospun fiber mats were used as carriers of GM for dermal delivery. Water­ soluble GM extracts with strong antioxidation activity were incorporated into the elec­ trospun PV A fiber mats. The morphology of both the neat and the GM extract-loaded electrospun fiber mats, the GM extract entrapment efficiency within the electrospun fiber mats, the swelling and weight loss behavior of both the neat and the GM extract­ loaded electrospun fiber mats in an aqueous medium, and the release characteristics of the extract from the GM extract-loaded electrospun fiber mats were investigated via antioxidant activity.

ELECTROSPUN PVA FIBER MATS AS EXTRACT CARRIERS 235 MATERIALS AND METHODS MATERIALS Poly(vinyl alcohol) (PVA) (degree of polymerization� 1600 and degree of hydrolysis � 97.5-99.5 mol%) was purchased from Fluka (Switzerland). GM was obtained from a farm in Chantaburi Province, Thailand. The source of 2,2-diphenyl-1-picryl-hydrazyl (DPPH) was Sigma-Aldrich (USA). Dimethyl sulfoxide (DMSO) was purchased from BDH Laboratories (UK). All other reagents and solvents were of analytical grade and used without further purification. PREPARATION OF GM EXTRACTS GM fruits were cleaned to remove any residual compost. The hulls were separated and then dried. All dried hulls were ground and placed in distilled water at 70°C at a hull powder-to-water ratio of 1 :4. The mixtures were boiled four times until no tannin content was observed. The macerate filtrate was dried at 40°--45°C in a hot-air oven. The dry powder was macerated at room temperature for seven days with distilled water. The extract was filtered and then evaporated to obtain the dry crude extracts. DPPH FREE-RADICAL SCAVENGING ACTIVITY The scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was carried out ac­ cording to the method of Blois (28). Briefly, dilutions of the test compounds (in 100% DMSO) were treated with an ethanolic solution of DPPH (100 µM) for 30 min at 37°C. The DMSO solvent was used as the control (i.e., 0% radical scavenging). The radical scavenging potential was determined photometrically by reaction with DPPH free radi­ cals in a microplate reader (Universal Microplate Analyzer, Models AOPUS0l and AI53601 Packard BioScience, USA) at 550 nm. The antioxiant activity was used as a marker for the presence of GM extracts, expressed as percent of radical scavenging and calculated as follows: Radical scavenging activity(%)=(1 -(A sampl / A concroi )) X 100 where Asam ple is the absorbence of the sample and Aconcrol is the absorbence of the control. PREPARATION OF NEAT AND GM EXTRACT-LOADED ELECTROSPUN PVA FIBER MATS AND CAST PVA FILMS A weighed amount of PV A powder was dissolved in distilled water at 80°C for 3 h to prepare a PVA solution at a fixed concentration of 10% w/v. After the solution was cooled to room temperature, GM extracts (2.5%, 5%, and 10% w/w, based on the weight of PV A) were added to the PV A solution under constant stirring for 4 h. Electrospinning of the prepared solutions was carried out by connecting the emitting electrode of positive polarity from a high-voltage DC power supply (D-ES30PN/M692, Gamma High Voltage Research, USA) to the solutions contained in a standard 50-ml syringe, the open end of which was attached to a gauge-20 flat-tipped stainless steel