Stacked ensemble learning on HaCaT cytotoxicity for skin irritation prediction: A case study on dipterocarpol

Skin irritation is an adverse effect associated with various substances, including chemicals, drugs, or natural products. Dipterocarpol, extracted from Dipterocarpus alatus, contains several skin benefits notably anticancer, wound healing, and antibacterial properties. However, the skin irritation of dipterocarpol remains unassessed. Quantitative structure-activity relationship (QSAR) is a recommended tool for toxicity assessment involving less time, money, and animal testing to access unavailable acute toxicity data. Therefore, our study aimed to develop a highly accurate machine learning-based QSAR model for predicting skin irritation. We utilized a stacked ensemble learning model with 1064 chemicals. We also adhered to the recommendations from the OECD for QSAR validation. Subsequently, we used the proposed model to explore the cytotoxicity of dipterocarpol on keratinocytes. Our findings indicate that the model displayed promising statistical quality in terms of accuracy, precision, and recall in both 10-fold cross-validation and test datasets. Moreover, the model predicted that dipterocarpol does not have skin irritation, which was confirmed by the cell-based assay. In conclusion, our proposed model can be applied for the risk assessment of skin irritation in untested compounds that fall within its applicability domain. The web application of this model is available at https://qsarlabs.com/#stackhacat.

Combinatory effects of Dipterocarpus alatus twig emulgel: Wound-restoring, antibacterial, and anti-inflammatory activities against methicillin-resistant Staphylococcus aureus-infected mouse superficial wounds

Dipterocarpus alatus has been used for the treatment of infectious skin diseases and ulcerative wounds in Thai traditional medicine. A major pathogen in human superficial skin infections is methicillin-resistant Staphylococcus aureus (MRSA). This study determined the wound healing, antibacterial, and anti-inflammatory activities of D. alatus twig emulgel against MRSA-infected mouse superficial skin wounds. Ethyl acetate-methanol crude extract of D. alatus twig was incorporated into emulgel at concentrations of 20 and 40 mg/g (D20 and D40) and its activity was compared to tetracycline emulgel (160 μg/g, Tetra). MRSA-infected superficial wounds demonstrated decreased skin barrier strength, increased transepidermal water loss (TEWL), and mast cell accumulation. Expression of toll-like receptor 2 (TLR-2), NF-κβ, TNFα, IL-1β, IL-6 and IL-10 genes were induced after MRSA infection. Daily application of 100 μL of D20 or D40 for 9 days restored skin barrier strength and TEWL while reducing mast cell and MRSA numbers compared to the non-treated group (MRSA-NT). The wounds treated with D20 and D40 were entirely healed on day 9. Expression of TLR-2 and cytokine-related genes NF-κβ, TNFα, IL-1β, IL-6 and IL-10 were normalized by treatment with either D20 or D40. Therefore, emulgel containing 20 to 40 mg/g ethyl acetate-methanol crude D. alatus twig extract is a good candidate for development as a topical formulation for MRSA-infected ulcerated wounds.

Effects of the Ethanol Extract of Dipterocarpus alatus Leaf on the Unpredictable Chronic Mild Stress-Induced Depression in ICR Mice and Its Possible Mechanism of Action

Treatment of the unpredictable chronic mild stress (UCMS) mice with the ethanol extract of Dipterocarpus alatus leaf attenuated anhedonia (increased sucrose preference) and behavioral despair (decreased immobility time in tail suspension test (TST) and forced swimming test (FST)). The extract not only decreased the elevation of serum corticosterone level and the index of over-activation of the hypothalamic-pituitary-adrenal (HPA) axis, caused by UCMS, but also ameliorated UCMS-induced up-regulation of serum- and glucocorticoid-inducible kinase 1 (SGK1) mRNA expression and down-regulation of cyclic AMP-responsive element binding (CREB) and brain-derived neurotrophic factor (BDNF) mRNAs in frontal cortex and hippocampus. In vitro monoamine oxidase (MAO) inhibition assays showed that the extract exhibited the partial selective inhibition on MAO-A. HPLC analysis of the extract showed the presence of flavonoids (luteolin-7-O-glucoside, kaempferol-3-glucoside, rutin) and phenolic acids (gallic acid, ferulic acid, and caffeic acid) as major constituents.

Anti-hyperuricemic and anti-inflammatory actions of vaticaffinol isolated from Dipterocarpus alatus in hyperuricemic mice

The present study was designed to examine the anti-hyperuricemic and anti-inflammatory effects and possible mechanisms of vaticaffinol, a resveratrol tetramer isolated from ethanol extracts of Dipterocarpus alatus, in oxonate-induced hyperuricemic mice. At 1 h after 250 mg·kg^-1 potassium oxonate was given, vaticaffinol at 20, 40, and 60 mg·kg^-1 was intragastrically administered to hyperuricemic mice once daily for seven consecutive days. Vaticaffinol significantly decreased serum uric acid levels and improved kidney function in hyperuricemic mice. It inhibited hepatic activity of xanthine dehydrogenase (XDH) and xanthine oxidase (XOD), regulated renal mRNA and protein levels of urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporter 1 (OAT1), organic cation transporter 1 (OCT1), OCT2, organic cation/carnitine transporter 1 (OCTN1), and OCTN2 in hyperuricemic mice. Moreover, vaticaffinol markedly down-regulated renal protein levels of NOD-like receptor 3 (NLRP3), apoptosis-associated speck-like (ASC), and Caspase-1, resulting in the reduction of interleukin (IL)-1β, IL-18, IL-6 and tumor necrosis factor-α (TNF-α) levels in this animal model. Additionally, HPLC and LC-MS analyses clearly testified the presence of vaticaffinol in the crude extract. These results suggest that vaticaffinol may be useful for the prevention and treatment of hyperuricemia with kidney inflammation.