Thunbergia laurifolia Leaf Extract Inhibits Glutamate-Induced Neurotoxicity and Cell Death through Mitophagy Signaling

Oxidative stress plays a crucial role in neurodegeneration. Therefore, reducing oxidative stress in the brain is an important strategy to prevent neurodegenerative disorders. Thunbergia laurifolia (Rang-jued) is well known as an herbal tea in Thailand. Here, we aimed to determine the protective effects of T. laurifolia leaf extract (TLE) on glutamate-induced oxidative stress toxicity and mitophagy-mediated cell death in mouse hippocampal cells (HT-22). Our results reveal that TLE possesses a high level of bioactive antioxidants by LC–MS technique. We found that the pre-treatment of cells with TLE prevented glutamate-induced neuronal death in a concentration-dependent manner. TLE reduced the intracellular ROS and maintained the mitochondrial membrane potential caused by glutamate. Moreover, TLE upregulated the gene expression of antioxidant enzymes (SOD1, SOD2, CAT, and GPx). Interestingly, glutamate also induced the activation of the mitophagy process. However, TLE could reverse this activity by inhibiting autophagic protein (LC3B-II/LC3B-I) activation and increasing a specific mitochondrial protein (TOM20). Our results suggest that excessive glutamate can cause neuronal death through mitophagy-mediated cell death signaling in HT-22 cells. Our findings indicate that TLE protects cells from neuronal death by stimulating the endogenous antioxidant enzymes and inhibiting glutamate-induced oxidative toxicity via the mitophagy–autophagy pathway. TLE might have potential as an alternative or therapeutic approach in neurodegenerative diseases.

Antioxidant Activity and Anti-Photoaging Effects on UVA-Irradiated Human Fibroblasts of Rosmarinic Acid Enriched Extract Prepared from Thunbergia laurifolia Leaves

The current study investigated the inhibiting effect on reactive oxygen species (ROS), reactive nitrogen species (RNS), and matrix metalloproteinase-1 (MMP-1) production in a cell-based study of standardized rosmarinic acid enriched extract (SRAEE) prepared from Thunbergia laurifolia leaves. HPLC chromatogram revealed that rosmarinic acid is a major component in prepared SRAEE, followed by caffeic acid. SRAEE exhibited antioxidant activity both in vitro and cell-based studies. SRAEE showed scavenging effects on nitric oxide and superoxide anion and inhibition effects on lipid peroxidation in vitro. SRAEE also inhibited ROS and MMP-1 production in normal human dermal fibroblast cells induced by H2O2 and UVA, respectively, without exerted cytotoxicity. Additionally, collagen degradation was protected by SRAEE induced by UVA. Nitric oxide and inducible nitric oxide synthase (iNOS) productions were also inhibited by SRAEE in RAW264.7 mouse macrophage cells induced by combined lipopolysaccharide (LPS)-interferon-γ (IFN-γ). The results indicated that SRAEE is a potential candidate as a natural pharmaceutical active ingredient for cosmeceutical product application.

A new species and a new record of Curcuma subgen. Curcuma (Zingiberaceae) from Northern Thailand

Saensouk S, Boonma T, Saensouk P. 2021. A new species and a new record of Curcuma subgen. Curcuma (Zingiberaceae) from Northern Thailand. Biodiversitas 22: 3617-3626. Recent fieldwork to study the species diversity of the Zingiberaceae family in Thailand and preparing a revision of the Curcuma genus for the Flora of Thailand, an undescribed species of Curcuma uses as traditional medicinal for more than two decades well known in the Thai vernacular name “Rang-Jued” was found, this vernacular name is also used to call the other two medicinal plants belonging to different families which are Thunbergia laurifolia Lindl. (Acanthaceae), and Crotalaria spectabilis Roth (Fabaceae), thus some villagers are named Curcuma rangjued as “Rang-Jued-Khamin” to communicate specifically identify species in order to use correct species for each utilization. While Thunbergia laurifolia was called "Rang-Jued-Thao", which "Thao" means "vine" refers to its habit and Crotalaria spectabilis was called "Rang-Jued-Ton" which "Ton" means "stem" refers to its erect stems. After comparing this undescribed species of Curcuma with its allies species, we found that this species did not match with any existing taxa, thus described with detailed illustrations, photographs, summaries for its distribution, ecology in the name of Curcuma rangjued Saensouk & Boonma and followed by a new record of C. cordata Wall. for Thailand which in the past has been determined as a synonym of C. petiolata Roxb. but now it is back to a recognized name once again. Both species in this study were found distributed in the northern region of Thailand and belong to Curcuma subgenus Curcuma, their description along with ecology, phenology, and a revised key to 28 species of Curcuma subgenus Curcuma in Thailand are also present for facilitating identification.

Formulations for effective detoxification derived fromthree medicinalplants: Thunbergia laurifolia,Clerodendrum disparifoliumand Rotheca serrata

Background: Based on the long history of medicinal use of Thunbergia laurifolia, Clerodendrum disparifolium and Rotheca serrata, the extract formulations of these species: T. laurifolia and C. disparifolium; T. laurifolia and R. serrata;and T. laurifolia, C. disparifolium and R. serrata, called formulas 1, 2 and 3, were created for detoxification testing to take more advantage of eachspecies. Objective: To estimate the detoxifying effects of studiedextract formulations on human cell and tissue culture as a preclinical trial. Methods: Themajor phytochemicals were derived by GC-MS. Thedetoxification efficacy of these formulations in cellsand DNA levelsby MTT and cometassays in toxic PBMCs (incubated with rice whisky or bathroom cleaner). Results: The phytochemical constituents were detected at 23.48% phytol and 43.03% oleamide in T. laurifolia; 12.88% oleamide, 20.93% 9,12,15-octadecatrien, 25.52% squalene, 22.19% butylated hydroxy toluene and 15.36% vitamin E in C. disparifolium; and 30.41% phytol, 32.78% oleamide, and12.20%, 9,12,15-octadecatrien-1-ol in R. serrata.The toxic cells treated with the plant formulas 1, 2 and 3 showed no IC50 values,but formulas 1 and 2 displayed higher efficaciesthandid formula 3. The comet assay indicated that the experiments (the treatment on toxic cells with the plant formulas) induced significant (p<0.05) DNA damage compared to the negative control due to poisoning occurring before administration of the plant formulas. The OTM of the controls was significantly (p<0.05) longer than the experimental samplesshowing significantly reduce toxicityof the created formulations. Conclusion: The formulas showed high detoxification efficacies and the formulations 1 and 2resulted inhigher levels of detoxification thanthe formulation3, especially immediate treatment after receiving toxic substances.