A new dilactone from the seeds of Gaultheria yunnanensis

Ginkgetin effectively mitigates collagen and AA-induced platelet activation via PLCγ2 but not cyclic nucleotide-dependent pathway in human

Platelets assume a pivotal role in the cardiovascular diseases (CVDs). Thus, targeting platelet activation is imperative for mitigating CVDs. Ginkgetin (GK), from Ginkgo biloba L, renowned for its anticancer and neuroprotective properties, remains unexplored concerning its impact on platelet activation, particularly in humans. In this investigation, we delved into the intricate mechanisms through which GK influences human platelets. At low concentrations (0.5-1 μM), GK exhibited robust inhibition of collagen and arachidonic acid (AA)-induced platelet aggregation. Intriguingly, thrombin and U46619 remained impervious to GK's influence. GK's modulatory effect extended to ATP release, P-selectin expression, intracellular calcium ([Ca2+ ]i) levels and thromboxane A2 formation. It significantly curtailed the activation of various signaling cascades, encompassing phospholipase Cγ2 (PLCγ2)/protein kinase C (PKC), phosphoinositide 3-kinase/Akt/glycogen synthase kinase-3β and mitogen-activated protein kinases. GK's antiplatelet effect was not reversed by SQ22536 (an adenylate cyclase inhibitor) or ODQ (a guanylate cyclase inhibitor), and GK had no effect on the phosphorylation of vasodilator-stimulated phosphoproteinSer157 or Ser239 . Moreover, neither cyclic AMP nor cyclic GMP levels were significantly increased after GK treatment. In mouse studies, GK notably extended occlusion time in mesenteric vessels, while sparing bleeding time. In conclusion, GK's profound impact on platelet activation, achieved through inhibiting PLCγ2-PKC cascade, culminates in the suppression of downstream signaling and, ultimately, the inhibition of platelet aggregation. These findings underscore the promising therapeutic potential of GK in the CVDs.

Neuroprotective Potential of Biflavone Ginkgetin: A Review

Neurological disorders are becoming more common, and there is an intense search for molecules that can help treat them. Several natural components, especially those from the flavonoid group, have shown promising results. Ginkgetin is the first known biflavonoid, a flavonoid dimer isolated from ginkgo (Ginkgo biloba L.). Later, its occurrence was discovered in more than 20 different plant species, most of which are known for their use in traditional medicine. Herein we have summarized the data on the neuroprotective potential of ginkgetin. There is evidence of protection against neuronal damage caused by ischemic strokes, neurotumors, Alzheimer's disease (AD), and Parkinson's disease (PD). Beneficial effects in ischemic strokes have been demonstrated in animal studies in which injection of ginkgetin before or after onset of the stoke showed protection from neuronal damage. AD protection has been the most studied to date. Possible mechanisms include inhibition of reactive oxygen species, inhibition of β-secretase, inhibition of Aβ fibril formation, amelioration of inflammation, and antimicrobial activity. Ginkgetin has also shown positive effects on the relief of PD symptoms in animal studies. Most of the available data are from in vitro or in vivo animal studies, where ginkgetin showed promising results, and further clinical studies should be conducted.

Sesquiterpenes from Kadsura coccinea attenuate rheumatoid arthritis-related inflammation by inhibiting the NF-κB and JAK2/STAT3 signal pathways

The roots of Kadsura coccinea is commonly used in Tujia ethnomedicine, named "heilaohu", having the effect of treating rheumatic arthritis (RA). Chemical investigation on the ethanol extract of heilaohu led to the isolation of one undescribed cuparane sesquiterpenoid, heilaohusesquiterpenoid A, one undescribed carotane sesquiterpenoids, heilaohusesquiterpenoid B, and eighteen sesquiterpene derivatives. Their structures were subsequently determined based on their 1D and 2D-NMR, HR-ESI-MS, and ECD spectroscopic data. Gaultheriadiolide was the most cytotoxic compound against the proliferation of rheumatoid arthritis-fibroblastoid synovial (RA-FLS) cells with an IC₅₀ value of 9.37 μM. In the same line, nine compounds exhibited significant inhibition effects against TNF-α and IL-6 release in the LPS-induced RAW264.7 cells with IC₅₀ values ranging between 1.03 and 10.99 μM. The potential molecular mechanisms of the active compounds against RA were established through pharmacological network analysis based on the initial screening results. Experimental validation showed that gaultheriadiolide suppressed inflammation by inhibiting the NF-kB and JAK2/STAT3 pathways. This study enriches the structural diversity of sesquiterpenes in K. coccinea and lays a foundation for further anti-RA and anti-inflammatory studies.

Metabolite Profiling of Eastern Teaberry (Gaultheria procumbens L.) Lipophilic Leaf Extracts with Hyaluronidase and Lipoxygenase Inhibitory Activity

The phytochemical profile and anti-inflammatory activity of Gaultheria procumbens dry lipophilic leaf extracts were evaluated. Forty compounds were identified by GC-MS, representing 86.36% and 81.97% of the petroleum ether (PE) and chloroform (CHE) extracts, respectively, with ursolic acid (28.82%), oleanolic acid (10.11%), methyl benzoate (10.03%), and methyl salicylate (6.88%) dominating in CHE, and methyl benzoate (21.59%), docosane (18.86%), and octacosane (11.72%) prevailing in PE. Three components of CHE were fully identified after flash chromatography isolation and spectroscopic studies as (6S,9R)-vomifoliol (4.35%), 8-demethyl-latifolin (1.13%), and 8-demethylsideroxylin (2.25%). Hyaluronidase and lipoxygenase inhibitory activity was tested for CHE (IC50 = 282.15 ± 10.38 μg/mL and 899.97 ± 31.17 μg/mL, respectively), PE (IC50 = 401.82 ± 16.12 μg/mL and 738.49 ± 15.92 μg/mL), and nine of the main constituents versus heparin (IC50 = 366.24 ± 14.72 μg/mL) and indomethacin (IC50 = 92.60 ± 3.71 μg/mL) as positive controls. With the best activity/concentration relationships, ursolic and oleanolic acids were recommended as analytical markers for the extracts and plant material. Seasonal variation of both markers following foliar development was investigated by UHPLC-PDA. The highest levels of ursolic (5.36-5.87 mg/g DW of the leaves) and oleanolic (1.14-1.26 mg/g DW) acids were observed between August and October, indicating the optimal season for harvesting.

Gaultheria: Phytochemical and pharmacological characteristics

The genus Gaultheria, comprised of approximately 134 species, is mostly used in ethnic drugs to cure rheumatism and relieve pain. Phytochemical investigations of the genus Gaultheria have revealed the presence of methyl salicylate derivatives, C₆-C₃ constituents, organic acids, terpenoids, steroids, and other compounds. Methyl salicylate glycoside is considered as a characteristic ingredient in this genus, whose anti-rheumatic effects may have a new mechanism of action. In this review, comprehensive information on the phytochemistry, volatile components and the pharmacology of the genus Gaultheria is provided to explore its potential and advance research.