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The fruits of Swietenia macrophylla King have been processed commercially to a variety of health foods and healthcare products and exhibited antidiabetic, antiinflammatory, antimutagenicity, antitumor activity, and so on. This study was aimed to examine the glucose consumption in human hepatoma HepG2 cells and the expression of PPARγ of limonoids isolated from the fruits of S. macrophylla.The phytochemical investigation of the fruits led to the isolation of ten limonoids which structures were elucidated by spectroscopic analysis as swietenine (1), khayasin T (2), 6-deoxyswietenine (3), 3-O-tigloylswietenolide (4), swietenolide (5), 3,6-O,O-diacetylswietenolide (6), 7-deacetoxy-7-oxogedunin (7), fissinolide (8), proceranolide (9), 7-deacetoxy-7α-hydroxygedunin (10), and compound 10 was isolated from this plant for the first time. The glucose consumption assay revealed that compounds 1, 2, 3, 5, and 9 could promote glucose consumption significantly in normal hyperglycemia-induced HepG2 cells, furthermore, compounds 1, 5, and 9 had a better effect on promoting glucose consumption in insulin-resistant HepG2 cells. In addition, compounds 1 and 5 could dramatically enhance the expression of PPARγ protein in insulin-resistant HepG2 cells according to the western blotting analysis result.How to cite this article: Duan J-Y, Wang Y-J, Chen W, et al.Limonoids isolated from fruits of Swietenia macrophylla king enhance glucose consumption in insulin-resistant HepG2 cells via activating PPARγ.

Cerebral ischemia and following reperfusion affects many people worldwide. To discover efficient therapeutic approaches, numerous natural products have been investigated. The current study investigated the protective effects of thevetiaflavone, a natural flavonoid obtained from Wikstroemia indica, and the associated mechanisms using PC12 cells induced by oxygen and glucose deprivation. As a result, thevetiaflavone improves cell viability and suppresses the leakage of lactate dehydrogenase from the cytoplasm. Further investigation of the mechanisms demonstrated that thevetiaflavone decreases overproduction of ROS and ameliorates ROS‑mediated mitochondrial dysfunction, including collapse of mitochondrial membrane potential and mitochondrial permeability transition pore opening. Thevetiaflavone reduces the intracellular Ca2+ level, which is closely associated with mitochondrial function and interplays with ROS. Furthermore, thevetiaflavone inhibits apoptosis in PC12 cells through upregulating the expression of Bcl‑2 and downregulating that of Bax and caspase‑3 in addition to increasing the activity of caspase‑3. These results further indicate the protective effects of thevetiaflavone in vivo and its application in the clinic.

Sesquiterpenes have been identified as promising ingredients for aviation fuels due to their high energy density and combustion heat properties. Despite the characterization of numerous sesquiterpene structures, studies testing their performance properties and feasibility as fuels are scarce. In this study, 122 sesquiterpenoid skeleton compounds, obtained from existing literature reports, are tested using group contribution and gaussian quantum chemistry methods to assess their potential as high‐energy aviation fuels. Seventeen sesquiterpene compounds exhibit good predictive performance and nine compounds are further selected for overproduction in yeast. Through fed‐batch fermentation, all compounds achieve the highest reported titers to date. Subsequently, three representative products, pentalenene, presilphiperfol‐1‐ene, and α‐farnesene, are selected, produced, purified in large quantities, and tested for use as potential fuels. The performance of pentalenene, presilphiperfol‐1‐ene, and their derivatives reveals favorable prospects as high‐energy aviation fuels.

Ischemic cerebral stroke is a severe cause of human death and disability. Natural products play an important role in the discovery of novel therapy for cerebral ischemia. Herein, we investigate the neuroprotective effects of sikokianin A identifiedfrom Wikstroemia indica using PC12 cell exposed to OGD/R. The results revealed sikokianin A can improve the poor viability and release of intracellular LDH in PC12 cells induced by OGD/R. Further studies have demonstrated the increased ROS and MDA together with reduced SOD activity were attenuated by sikokianin A. Meanwhile, decreased mitochondrial membrane potential, activated Caspase-3, down-regulated Bcl-2 and up-regulated Bax were reversed. These results indicate the protective effects of sikokianin A are associated with inhibiting oxidative stress and apoptosis resulting from OGD/R. Additionally, sikokianin A can activate Nrf2 and downstream HO-1 in PC12 cells treated by OGD/R, which implied Nrf2/HO-1 signaling pathway was involved in the protective effects of sikokianin A.