Anti-Amyloidogenic and Cyclooxygenase Inhibitory Activity of Guettarda speciosa

Guettarda crispiflora Vahl Methanol Extract Ameliorates Acute Lung Injury and Gastritis by Suppressing Src Phosphorylation

Many species in the genus Guettarda are known to exert anti-inflammatory effects and are used as traditional medicinal plants to treat various inflammatory symptoms. However, no studies on the inflammatory activities of Guettarda crispiflora Vahl have been reported. The aim of the study was to investigate in vitro and in vivo the anti-inflammatory effects of a methanol extract of Guettarda crispiflora Vahl (Gc-ME). To determine the anti-inflammatory activity of Gc-ME, lipopolysaccharide (LPS)-, poly(I:C)-, or Pam3CSK4-treated RAW264.7 cells, HCl/EtOH- and LPS-treated mice were employed for in vitro and in vivo tests. LPS-induced nitric oxide production in RAW264.7 cells was determined by Griess assays and cytokine gene expression in LPS-activated RAW264.7 cells, confirmed by RT- and real-time PCR. Transcriptional activation was evaluated by luciferase reporter gene assay. Target protein validation was assessed by Western blot analysis and cellular thermal shift assays (CETSA) with LPS-treated RAW264.7 and gene-transfected HEK293 cells. Using both a HCl/EtOH-induced gastritis model and an LPS-induced lung injury model, inflammatory states were checked by scoring or evaluating gastric lesions, lung edema, and lung histology. Phytochemical fingerprinting of Gc-ME was observed by using liquid chromatography-mass spectrometry. Nitric oxide production induced by LPS and Pam3CSK4 in RAW264.7 cells was revealed to be reduced by Gc-ME. The LPS-induced upregulation of iNOS, COX-2, IL-6, and IL-1β was also suppressed by Gc-ME treatment. Gc-ME downregulated the promotor activities of AP-1 and NF-κB triggered by MyD88- and TRIF induction. Upstream signaling proteins for NF-κB activation, namely, p-p50, p-p65, p-IκBα, and p-Src were all downregulated by Ch-EE. Moreover, Src was revealed to be directly targeted by Gc-ME. This extract, orally treated strongly, attenuated the inflammatory symptoms in HCl/EtOH-treated stomachs and LPS-treated lungs. Therefore, these results strongly imply that Guettarda crispiflora can be developed as a promising anti-inflammatory remedy with Src-suppressive properties.

Neuroprotective effects on amyloid-beta induced cytotoxicity of Pandanus clementis Merr

The present study determined the neuroprotective potential of the alcoholic and aqueous extracts of Pandanus clementis Merr. (Pandanaceae) to protect the neuroblastoma SH-SY5Y cells against amyloid-beta _1-42 (Aβ) cytotoxicity. Inhibition of Aβ aggregation was determined by Thioflavin T (ThT) assay, and in vitro neuroprotective cell viability, intracellular reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were evaluated with human neuroblastoma SH-SY5Y cells insulted with Aβ. Chromatographic separation on the alcoholic extract yielded known phytosterols. Results showed that pretreatment of the SH-SY5Y cells with the P. clementis extracts increased cell viability and MMP, and decreased ROS, suggesting protective effects. Hence, P. clementis extract has promising neuroprotective therapeutic potential.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02889-3.

Diaportheone A Analogues Instigate a Neuroprotective Effect by Protecting Neuroblastoma SH-SY5Y Cells from Oxidative Stress

Alzheimer's disease (AD) remains an incurable neurodegenerative illness. Oxidative stress resulting in the formation of reactive oxygen species (ROS) and the abnormal deposition of amyloid-beta (Aβ) are the major pathological hallmarks associated with AD. In search for small molecules targeting multiple pathways of AD and of no known molecular targets, the neuroprotective effects of the synthetic chromones diaportheone A1 and diaportheone A2, analogues of the natural product diaportheone A, were investigated. Chromones are heterocyclic compounds bearing the benzoannelated γ-pyrone moiety and were regarded as an important class of organic molecules due to their diverse pharmacological activities. The influence of the compounds on the inhibition of Aβ aggregation was determined by Thioflavin T (ThT) assay, and the cell viability, ROS, and mitochondrial membrane potential were evaluated with human neuroblastoma SH-SY5Y cells. Results showed that both compounds inhibited the Aβ aggregation at 80.41% and 73.68% for diaportheone A1 and diaportheone A2, respectively. Increased cell viabilities were observed from the protection by both compounds using Aβ- or H₂O₂-induced SH-SY5Y cells. Both compounds also reduced the intracellular ROS level in Aβ- or H₂O₂-induced SH-SY5Y cells at 10 and 20 μM concentrations, and increased the mitochondrial membrane potentials in Aβ-induced SH-SY5Y cells at 20 μM concentration. Molecular docking experiments using the Aβ protein models 2MXU and 2BEG also indicated a good agreement with the experimental data. The results demonstrated for the first time the oxidative stress effects associated with the chromones diaportheone A1 and diaportheone A2 as potential neuroprotective therapeutic agents against AD.

Neuroprotective potential of the oxindole alkaloids isomitraphylline and mitraphylline in human neuroblastoma SH-SY5Y cells

The purified oxindole alkaloids, isomitraphylline and mitraphylline from Uncaria perrottetii, revealed their ability to break amyloid aggregates in vitro suggesting their therapeutic potentials in Alzheimer's disease (AD). Thioflavin-T assay for assessing amyloid-beta (Aβ) aggregation of these alkaloids exhibited inhibitions at 60.321% ± 2.61 (50 μM) for isomitraphylline and 43.17% ± 3.48 (50 μM) for mitraphylline. Neuroprotective effects were elaborated against Aβ-induced SH-SY5Y cells at 20 μM and 10 μM for isomitraphylline, and 20 μM for mitraphylline. In addition, both alkaloids attenuated and protected the H₂O₂-induced SH-SY5Y cell cytotoxicity at 20 μM. The intracellular ROS levels of SH-SY5Y cells from H₂O₂-induced oxidative stress were reduced at 20 μM and 10 μM, and the mitochondrial membrane potentials of Aβ-induced SH-SY5Y cells were protected at 20 μM. The overall results suggested the potentials of both alkaloids to target certain pathological biomarkers of AD and could be further investigated as therapeutic or preventive drug leads against AD.

Special Issue "Plant Extracts: Biological and Pharmacological Activity"

The use of plant extracts for therapeutic purposes knows a wide diffusion [...].

Quantitative ethnopharmacological documentation and molecular confirmation of medicinal plants used by the Manobo tribe of Agusan del Sur, Philippines

BACKGROUND

The Philippines is renowned as one of the species-rich countries and culturally megadiverse in ethnicity around the globe. However, ethnopharmacological studies in the Philippines are still limited especially in the most numerous ethnic tribal populations in the southern part of the archipelago. This present study aims to document the traditional practices, medicinal plant use, and knowledge; to determine the relative importance, consensus, and the extent of all medicinal plants used; and to integrate molecular confirmation of uncertain species used by the Agusan Manobo in Mindanao, Philippines.

METHODS

Quantitative ethnopharmacological data were obtained using semi-structured interviews, group discussions, field observations, and guided field walks with a total of 335 key informants comprising of tribal chieftains, traditional healers, community elders, and Manobo members of the community with their medicinal plant knowledge. The use-report (UR), use categories (UC), use value (UV), cultural importance value (CIV), and use diversity (UD) were quantified and correlated. Other indices using fidelity level (FL), informant consensus factors (ICF), and Jaccard's similarity index (JI) were also calculated. The key informants' medicinal plant use knowledge and practices were statistically analyzed using descriptive and inferential statistics.

RESULTS

This study enumerated the ethnopharmacological use of 122 medicinal plant species, distributed among 108 genera and belonging to 51 families classified in 16 use categories. Integrative molecular approach confirmed 24 species with confusing species identity using multiple universal markers (ITS, matK, psbA-trnH, and trnL-F). There was strong agreement among the key informants regarding ethnopharmacological uses of plants, with ICF values ranging from 0.97 to 0.99, with the highest number of species (88) being used for the treatment of abnormal signs and symptoms (ASS). Seven species were reported with maximum fidelity level (100%) in seven use categories. The correlations of the five variables (UR, UC, UV, CIV, and UD) were significant (rs ≥ 0.69, p < 0.001), some being stronger than others. The degree of similarity of the three studied localities had JI ranged from 0.38 to 0.42, indicating species likeness among the tribal communities. Statistically, the medicinal plant knowledge among respondents was significantly different (p < 0.001) when grouped according to education, gender, social position, occupation, civil status, and age but not (p = 0.379) when grouped according to location. This study recorded the first quantitative ethnopharmacological documentation coupled with molecular confirmation of medicinal plants in Mindanao, Philippines, of which one medicinal plant species has never been studied pharmacologically to date.

CONCLUSION

Documenting such traditional knowledge of medicinal plants and practices is highly essential for future management and conservation strategies of these plant genetic resources. This ethnopharmacological study will serve as a future reference not only for more systematic ethnopharmacological documentation but also for further pharmacological studies and drug discovery to improve public healthcare worldwide.