Two New Apotirucallane-Type Triterpenoids from the Pericarp of Toona sinensis and Their Ability to Reduce Oxidative Stress in Rat Glomerular Mesangial Cells Cultured under High-Glucose Conditions

Abstract

Hyperglycemia is a strong risk factor for chronic complications of diabetes. Hyperglycemic conditions foster not only the production of reactive oxygen species (ROS), but also the consumption of antioxidants, leading to oxidative stress and promoting the occurrence and progression of complications. During our continuous search for antioxidant constituents from the pericarp of Toona sinensis (A. Juss.) Roem, we isolated two previously unreported apotirucallane-type triterpenoids, toonasinensin A (1) and toonasinensin B (2), together with five known apotirucallane-type triterpenoids (3–7) and two known cycloartane-type triterpenoids (8–9) from the pericarp. Compounds 8–9 were obtained from T. sinensis for the first time. Their structures were characterized based on interpretation of spectroscopic data (1D, 2D NMR, high-resolution electrospray ionization mass spectra, HR-ESI-MS) and comparison to previous reports. Compounds (2, 4, 6, 7, and 9) were able to inhibit proliferation against rat glomerular mesangial cells (GMCs) cultured under high-glucose conditions within a concentration of 80 μM. Compounds (2, 6, and 7) were tested for antioxidant activity attributable to superoxide dismutase (SOD), malondialdehyde (MDA), and ROS in vitro, and the results showed that compounds (2, 6, and 7) could significantly increase the levels of SOD and reduce the levels of MDA and ROS. The current studies showed that apotirucallane-type triterpenoids (2, 6, and 7) might have the antioxidant effects against diabetic nephropathy.

Traditional Uses, Chemical Constituents and Pharmacological Activities of the Toona sinensis Plant

“…T. sinensis, a deciduous woody plant native to Eastern and Southeastern Asia, is used as a vegetable source in China and Malaysia and as animal fodder in India [14,15]. The T. sinensis plant, a unique tree species in China, is popularly known as "Xiang Chun", In this review, we compile the progress on phytochemical studies over the past few decades, with all the elucidated compounds listed.…”

“…T. sinensis, a deciduous woody plant native to Eastern and Southeastern Asia, is used as a vegetable source in China and Malaysia and as animal fodder in India [14,15]. The A phytochemical investigation is a critical step in understanding the therapeutic potential of medicinal plants.…”

“…The C-17 side chain is an α configuration. At present, nine tirucallane triterpenoids (12)(13)(14)(15)(16)(17)(18)(19)(20) have been isolated from the barks, stem barks and seeds of T. sinensis. Three tirucallane triterpenoids (12, 16 and 17) have been isolated from the barks of T. sinensis [24,26].…”

“…Three tirucallane triterpenoids (12, 16 and 17) have been isolated from the barks of T. sinensis [24,26]. Three tirucallane triterpenoids (13)(14)(15) have been isolated from the seeds of T. sinensis [25]. Three tirucallane triterpenoids (18)(19)(20) have been isolated from the stem barks of T. sinensis [23] (Figure 3).…”

Bioactive Usual and Unusual Triterpenoids Derived from Natural Sources Used in Traditional Medicine

“…Roem (Meliaceae) is a well‐known Chinese medicine used throughout Asia and found to be a rich source of apotirucallanes that is toonasinensin A ( 85 ), toonasinensin B ( 86 ), toonasinensin C, toonasinensin D, toonasinensin E, 21 β ‐O‐methylmelianodiol, and 21 α ‐O‐methylmelianodiol ( Figure 5). [59] …”