Pharmacognostic researches on pinus species growing in Turkey

Current environmental factors and lifestyles deteriorate the balance of oxidants and antioxidants, and hence, oxidative stress and various diseases trigger in the human body. Substantial evidence suggests that oxidative stress is associated directly with diabetes and its microvascular and cardiovascular complications. Numerous scientific research has indicated that natural products could prevent the body from oxidative stress and alleviate many oxidative stress-related diseases. Pycnogenol®, a patented-standardized extract from P. pinaster barks, is one of the pharmacologically active natural products. This thesis was planned to evaluate the phytochemical profile, antioxidant and anti-diabetic activities of hot water extracts from the barks of two naturally growing Pinus species in Turkey; P. brutia Ten., P. pinea L., and one cultivated species in Turkey; P. pinaster Ait. Their chemical and activity profiles were compared to Pycnogenol® before and after submitting to an in vitro gastrointestinal human digestion simulation system. In vitro antioxidant assays indicated that hot water bark extracts of all studied plants possess high antioxidant activity in terms of free radical scavenging, metal-reducing activity, and total antioxidant activity. In addition, the results showed that all studied extracts had potent inhibitory activities on α-glucosidase, α-amylase enzymes and advanced-glycation end products (AGEs). The total phenolic, phenolic acid, proanthocyanidin, and flavonoid contents and also the amounts of some proanthocyanidins (proanthocyanidin A1, a proanthocyanidin B1/B2 mixture, proanthocyanidin C1), and flavan-3-ol derivatives (catechin/epicatechin mixture, epigallocatechin, epigallocatechin gallate, and catechin gallate), and several other phenolic components (taxifolin, caffeic acid, and ferulic acid) were measured to reveal the phytochemical contents of all studied extracts. High Performance Thin Layer Chromatography (HPTLC) system was used to identify and quantify of these metabolites. The results indicated that even though in vitro human gastrointestinal system negatively influenced the phytochemical profile, antioxidant and anti-diabetic potentials, all extracts possess high phenolic content and potent biological activities. Key words: Pinus species, Phenolic compounds, Antioxidant activity, In vitro Gastrointestinal Digestion Simulation system, HPTLC, Antidiabetic Activity