Asiatic acid improves high-fat-diet-induced osteoporosis in mice via regulating SIRT1/FOXO1 signaling and inhibiting oxidative stress

Saturated fatty acids negatively affect musculoskeletal tissues in vitro and in vivo

Fish oils rank among the world's most popular nutritional supplements and are purported to have numerous health benefits. Previous work suggested that fish oils increase collagen production; however, the effect of fish oils on musculoskeletal health is poorly understood. Further, the divergent effects of omega-3 (Ω3FA) and saturated fatty acids (SFA) remains poorly understood. We tested the effects of Ω3FA and SFAs on in vitro-engineered human ligament (EHL) function. EHLs were treated with bovine serum albumin (BSA)-conjugated eicosapentaenoic acid (EPA, 20:5(n-3)), palmitic acid (PA, 16:0), or a BSA control for 6 days. EPA did not significantly alter, whereas PA significantly decreased EHL function and collagen content. To determine whether this was an in vitro artifact, mice were fed a control or high-lard diet for 14 weeks and musculoskeletal mass, insulin sensitivity, and the collagen content, and mechanics of tendon and bone were determined. Body weight was 40 % higher on a HFD, but muscle, tendon, and bone mass did not keep up with body weight resulting in relative losses in muscle mass, tendon, and bone collagen, as well as mechanical properties. Importantly, we show that PA acutely decreases collagen synthesis in vitro to a similar extent as the decrease in collagen content with chronic treatment. These data suggest that Ω3FAs have a limited effect on EHLs, whereas SFA exert a negative effect on collagen synthesis resulting in smaller and weaker musculoskeletal tissues both in vitro and in vivo.

Rapid Separation of Asiatic Acid, Quercetin, and Kaempferol from Traditional Chinese Medicine Centella asiatica (L.) Urban Using HSCCC-Semi-Prep-HPLC and the Assessment of Their Potential as Fatty Acid Synthase Inhibitors

The main objective of this study was to rapidly separate asiatic acid (AA), quercetin (QCN), and kaempferol (KPL) from Centella asiatica (L.) Urban using high-speed counter-current chromatography (HSCCC) in tandem with the UV detector of semipreparative high-performance liquid chromatography (Semi-Prep-HPLC) and to evaluate their potential as inhibitors of fatty acid synthetase (FAS). To efficiently prepare large amounts of AA, QCN, and KPL from Centella asiatica (L.) Urban, rapid and simple methods by HSCCC were established respectively based on the partition coefficients (K values) of crude samples. The conditions of HSCCC-Semi-Prep-HPLC for the large-scale separation of AA, QCN, and KPL from Centella asiatica (L.) Urban were established and optimized. This included selecting the solvent system, flow rate, rotation speed, and so on. HSCCC-Semi-Prep-HPLC was successfully applied to separate and purify AA, QCN, and KPL, with n-hexane-n-butanol-methanol-water (3 : 1 : 3 : 3, V : V : V : V) as the solvent system for AA, which was detected at a wavelength of 210 nm with the stationary phase retention of 70%, and with n-hexane-ethyl acetate-methanol-water (0.8 : 0.9 : 1.2 : 1, V : V : V : V) as the solvent system for the co-separation of QCN and KPL, which was detected at a wavelength of 254 nm with the stationary phase retention of 65%. AA could be isolated at a large scale with high purity (>91.0%) in only one-step HSCCC-Semi-Prep-HPLC separation (within 150 min) under the optimized conditions. Meanwhile, QCN and KPL could be simultaneously isolated at a large scale with high purity (>99.1%) by another one-step HSCCC-Semi-Prep-HPLC separation (within 240 min) under the optimized conditions. The assessment of inhibition potential revealed that AA exhibited the strongest inhibitory effect on FAS, with an IC50 of 9.52 ± 0.76 μg/mL. Madecassic acid (MA) followed closely with IC50 values of 10.84 ± 0.92 μg/mL. QCN and KPL showed similar and relatively weaker inhibitory effects on FAS, with IC50 values of 43.09 ± 2.98 μg/mL and 36.90 ± 1.83 μg/mL, respectively. Overall, the HSCCC-Semi-Prep-HPLC method proved to be a highly efficient and reliable technique for separating AA, QCN, and KPL from Centella asiatica (L.) Urban, and the isolated compounds showed potential as FAS inhibitors.

Neuroprotective mechanisms of Asiatic acid

Asiatic acid (AA) is the most crucial component of Asiaticoside in many edible and medicinal plants. It has diverse biological activities such as anti-inflammatory, antioxidant, anti-infective, and anti-tumor. Additionally, AA has been intensively studied in the last decades. It has shown great potential in the treatment of various neurological diseases such as spinal cord injury (SCI), cerebral ischemia, epilepsy, traumatic brain injury (TBI), neural tumors, Alzheimer's disease (AD), and Parkinson's disease (PD). Moreover, AA provides pertinent data for neuroprotective signaling pathways, and its substantial neuroprotective ability makes it a novel candidate for developing drugs that target the central nervous system.