This paper presents and discusses 30 cases of cadavers that had been transferred for forensic entomology investigations to the Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, northern Thailand, from 2000 to 2006. Variable death scenes were determined, including forested area and suburban and urban outdoor and indoor environments. The fly specimens found in the corpses obtained were the most commonly of the blow fly of family Calliphoridae, and consisted of Chrysomya megacephala (F.), Chrysomya rufifacies (Macquart) Chrysomya villeneuvi Patton, Chrysomya nigripes Aubertin, Chrysomya bezziana Villeneuve, Chrysomya chani Kurahashi, Lucilia cuprina (Wiedemann), Hemipyrellia ligurriens (Wiedemann), and two unknown species. Flies of the family Muscidae [Hydrotaea spinigera Stein, Synthesiomyia nudiseta (Wulp)], Piophilidae [Piophila casei (L.)], Phoridae [Megaselia scalaris (Loew)], Sarcophagidae [Parasarcophaga ruficornis (F.) and three unknown species], and Stratiomyiidae (Sargus sp.) were also collected from these human remains. Larvae and adults of the beetle, Dermestes maculatus DeGeer (Coleoptera: Dermestidae), were also found in some cases. Chrysomya megacephala and C. rufifacies were the most common species found in the ecologically varied death scene habitats associated with both urban and forested areas, while C. nigripes was commonly discovered in forested places. S. nudiseta was collected only from corpses found in an indoor death scene.

We report a forensic entomology case associated with human myiasis in Chiang Mai Province, northern Thailand. The remains of a 53-yr-old-male were concurrently infested with third instars of the two blow fly species, Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart), near a severe tumor lesion presented on the lower right leg. The presence of third instars, approximately 5 d old, on the day following postmortem indicated that myiasis occurred before death. This is the first report of both fly species acting as a myiasis-producing agent in Thailand. Unsynchronized data between the age of fly larvae due to myiasis premortem and verified age/ condition of the corpse suggest a potential complication and error in the estimation of postmortem interval if other predisposition fly infestations are not considered.

Previous studies presented evidence that plants contain antioxidants that have free radical-scavenging properties. Overproduction of free radicals leads to oxidative stress, a factor associated with a variety of diseases, such as diabetes. Cytochrome P450 2E1 enzymes (CYP2E1) are involved in drug metabolism in the liver and metabolism of DNA-reaction generating intra-mitochondrial ROS, which leads to micro- and macro-vascular pathology in diabetes. Plant-based chemicals can affect CYP2E1 enzymes and related defense mechanisms, possibly leading to protection against oxidative stress. We investigated the effect of Solanum torvum (ST) extracts on the inhibition of CYP2E1 activity in human liver microsomes. ST extract was analyzed for antioxidant activity by the ABTS method. Polyphenolic compounds were measured by the total phenol content using the Folin-Ciocalteau reagent. Flavonoid and tannin content were analyzed by standard methods. Oxidative stress was evaluated by measuring lipid peroxidation by TBARS and superoxide anion scavenging levels in plasma from diabetic patients. Results showed that 10 mg/ml of ST had CYP2E1 catalytic inhibiting activity (57.16 %). The IC50 value of CYP2E1 catalytic inhibiting activity level was 5.14 mg/ml by concentration in a dependent manner. One gram of concentrated ST extract had an antioxidant activity index of 3.68 mg of trolox and 360.53 mg of ascorbic acid equivalent. Effects on free radical-scavenging, as measured by TBARS and superoxide anion, showed IC50 values of 20.60 and 10.26 microg/ml, respectively. Polyphenolic compounds found included phenol, flavonoid and tannin, measuring 160.30, 104.36 and 65.91 mg/g, respectively. These results imply that ST is a natural source of polyphenolic antioxidants, which have cytochrome P450 2E1 enzyme inhibiting and free radical scavenging properties, as related to lipid peroxidation and superoxide anion activity. ST could potentially be used for reducing oxidative stress in diabetes. Study for usage as a conventional medicine, including dosage and chronic toxicity in humans, should be pursued.

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