Antihyperglycemic activity of fruit extracts of Sri Lankan endemic species <i>Garcinia quaesita</i> Pierre “Rathgoraka” and its isolated compound, garcinol

Abstract

The dried fruit of Garcinia quaesita Pierre (Clusiaceae), is a well-known endemic spice in Sri Lanka and has been documented in traditional medicine as an antidiabetic agent. The antihyperglycemic effect of cold water, hot water, water : acetone fruit extracts of G. quaesita and its isolated compound, garcinol in streptozotocin-induced diabetic rats was studied. The percentage improvements of glucose tolerance upon total area under the oral glucose tolerance curve in cold water, hot water and water:acetone extracts of G. quaesita (1.0 g/kg) were 6.2 %, 7.4 % and 8.1 %, respectively. The isolated compound, garcinol at the three selected doses (10 mg/kg, 20 mg/kg, 30 mg/kg), showed a dose dependent, antihyperglycemic activity of 23.6 %, 26.5 %, 31.1 % respectively compared to glibenclamide (0.5 mg/kg) (36.1 %) (p<0.05). The selected extracts of G. quaesita exhibited significant antihyperglycemic activity in streptozotocin-induced diabetic rats. The isolated compound, garcinol has significantly higher antihyperglycemic activity than the respective crude extracts. Accordingly, endemic dried fruits of G. quaesita and its isolated compound garcinol are promising antihyperglycemic agents and /or drug leads that would be beneficial in the management of diabetes mellitus.

Antioxidant and Antidiabetic Potentials of a Standardized Polyherbal Mixture Used in Traditional Medicine

“…This might be due to the presence of antidiabetic and antioxidant compounds and inhibitors of carbohydrate digestion enzymes. These results corroborate with those of other in vitro studies and the antihyperglycemic effect of hexane and ethyl acetate extracts would be due to the availability of a higher number of antidiabetic compounds, such as mahanimbine, isomahanimbine, koenimbidine, murrayacine koenimbine, myricetin, diallyl sulfide, diallyl disulfide, diallyl trisulfide, piperine and garcinol, present in the selected plants and the synergism of the active phytoconstituents [16,[71][72][73][74][75][76] .…”

“…From the hexane extract, piperine and β-pinene have been recorded as the major isolated compounds, while β-caryophyllene has been isolated as the major compound from the ethyl acetate extract of PN seeds [46][47][48] . Garcinol has been recorded as the major isolated compound from the hexane extract of GQ fruits, as per literature reports [16] . Those characteristic peaks in the HPLC profile of hexane extract and ethyl acetate extract, therefore, may be due to the presence of either of the aforementioned compounds.…”

“…Several previous studies has investigated the antidiabetic potential of the above individual plants, plant parts and their isolated compounds [12][13][14][15] . However, there are limited details on the blood glucose lowering property of GQ except in the one reported study of hypoglycemic activity of three extracts of the plant and its isolated compound of garcinol [16] . In addition, our group recently identified that cold water, hot water and water acetone extracts of the above mentioned polyherbal mixture have no acute or subchronic toxicity [17] .…”

Sub-acute antihyperlipidemic and antihyperglycemic activity of the hexane extract of a polyherbal mixture in streptozotocin-induced diabetic rats

“…The plant extract of the A. sativum showed significant reduction in serum glucose, triglyceride and total cholesterol levels in diabetic rats (Eidi et al, 2006). There are few reports of antihyperglycemic and antihyperlipidemic effects of the G. quaesita in addition to a study on the antihyperglycemic activity of three selected extracts of the plant by our research group (Liyanagamage et al, 2020a). In addition, subchronic and acute toxicity profile of the hot water and water: acetone extract of above polyherbal mixture was also assessed and found that it is safe and effective for in vivo use (Liyanagamage et al, 2020b).…”

“…In view of present investigation, antidiabetic effect of the plant mixture of selected polyherbal mixture may be due to potentiation of insulin synthesis and secretion from existing β cells in Langerhans. In addition, the antihyperglycemic effect of plant extract would be due to the reported availability of a higher number of antidiabetic compounds such as mahanimbine, isomahanimbine, koenimbidine, murrayacine and koenimbine, myricetin, diallyl sulfide, diallyl disulfide, diallyl trisulfide, piperine and garcinol present in the selected plants and the synergism of the active phytoconstituents (Dineshkumar et al, 2010;Handral et al, 2012;Padiya and Banerjee, 2013;Park et al, 2016;Jain et al, 2017;Radi´c et al, 2019;Liyanagamage et al, 2020a).…”