Geissoschizoline, a promising alkaloid for Alzheimer's disease: Inhibition of human cholinesterases, anti-inflammatory effects and molecular docking.

Due to the lack of effective pharmacotherapy options to treats Alzheimer's disease, new strategies have been approached in the search for multi-target molecules as therapeutic options. In this work, four indole alkaloids, geissoschizoline, geissoschizone, geissospermine, and 3',4',5',6'-tetradehydrogeissospermine were isolated from Geissospermum vellosii (Pao pereira) and evaluated for their anticholinesterase activities. While geissospermine inhibited only butyrylcholinesterase (BChE), the other alkaloids behaved as non-selective inhibitors of acetylcholinesterase (AChE) and BChE. In cell viability tests, only geissoschizoline was not cytotoxic. Therefore, geissoschizoline actions were also evaluated in human cholinesterases, where it was twice as potent inhibitor of hBChE (IC50 = 10.21 ± 0.01 µM) than hAChE (IC50 = 20.40 ± 0.93 µM). On enzyme kinetic studies, geissoschizoline presented a mixed-type inhibition mechanism for both enzymes. Molecular docking studies pointed interactions of geissoschizoline with active site and peripheral anionic site of hAChE and hBChE, indicating a dual site inhibitor profile. Moreover, geissoschizoline also played a promising anti-inflammatory role, reducing microglial release of NO and TNF-α at a concentration (1 µM) ten and twenty times lower than the IC50 values of hBChE and hAChE inhibition, respectively. These actions give geissoschizoline a strong neuroprotective character. In addition, the ability to inhibit hAChE and hBChE, with approximate inhibitory potencies, accredits this alkaloid for therapeutic use in the moderate to severe phase of AD. Thus, geissoschizoline emerges as a possible multi-target prototype that can be very useful in preventing neurodegeneration and restore neurotransmission.

Extracts of the Medicinal Plants Pao Pereira and Rauwolfia vomitoria Inhibit Ovarian Cancer Stem Cells In Vitro.

Ovarian cancer has an enrichment of cancer stem cells (CSCs) which contribute to the treatment resistant tumor's high rate of recurrence and metastasis. Here we investigated 2 plant extracts from the medicinal plants Pao Pereira (Pao) and Rauwolfia vomitoria (Rau) each for their activities against ovarian CSCs. Both Pao and Rau inhibited overall proliferation of human ovarian cancer cell lines with IC50 ranging from 210 to 420 µg/mL and had limited cytotoxicity to normal epithelial cells. Ovarian CSC population was examined using cell surface markers and tumor spheroid formation assays. The results showed that both Pao and Rau treatment significantly reduced the ovarian CSC population. Pao and Rau had similar activities in inhibiting ovarian CSCs, with IC50s of ~120 µg/mL for 24 hours treatment, and ~50 µg/mL for long-term tumor spheroid formation. Nuclear ß-catenin levels were decreased, suggesting suppression of Wnt/ß-catenin signaling pathway. Taken together, data here showed that Pao and Rau both inhibited ovarian cancer stem cells, probably in preference to the bulk of tumor cells. Further mechanistic studies and in vivo investigation validating these findings are warranted, given that inhibition of cancer stem cells holds the promise of comprehensively inhibiting cancer metastasis, drug resistance and recurrence.

Pao Pereira extract suppresses benign prostatic hyperplasia by inhibiting inflammation-associated NFκB signaling.

BACKGROUND: Our previous study revealed the extract from the bark of an Amazonian tree Pao Pereira can suppress benign prostatic hyperplasia (BPH) in a rat model. Herein, we examined its inhibitory effects on human BPH cells and dissect its molecular mechanism. METHODS: We applied Pao extract to human BPH epithelial BPH-1 and prostate myofibroblast WPMY-1 cells. Cell viability, apoptosis and immunoblotting were performed, followed by gene expression profiling and gene set enrichment analysis (GSEA) to detect the differentially expressed genes and signaling pathway induced by Pao extract. Human ex vivo BPH explant organ culture was also used to examine the effects of Pao extract on human BPH tissues. RESULTS: Pao extract treatment inhibited viability and induced apoptosis in human BPH-1 and WPMY-1 cells. Gene expression profiling and the following validation indicated that the expression levels of pro-apoptotic genes (eg. PCDC4, CHOP and FBXO32) were induced by Pao extract in both two cell lines. GSEA further revealed that Pao extract treatment was negatively associated with the activation of NFκB signaling. Pao extract suppressed the transcriptional activity of NFκB and down-regulated its target genes involved in inflammation (CXCL5, CXCL6 and CXCL12) and extracellular matrix (ECM) remodeling (HAS2, TNC and MMP13) in both cultured cells and human ex vivo BPH explants. CONCLUSION: In both BPH epithelial and stromal cells, Pao extract induces apoptosis by upregulating the pro-apoptotic genes and inhibiting the inflammation-associated NFκB signaling via reducing phosphorylation of NFκB subunit RelA. Our data suggest that Pao extract may be a promising phytotherapeutic agent for BPH.

Extract of the Medicinal Plant Pao Pereira Inhibits Pancreatic Cancer Stem-Like Cell In Vitro and In Vivo.

Pancreatic cancers are enriched with cancer stem-like cells (CSCs), which are resistant to chemotherapies, and responsible for tumor metastasis and recurrence. Here, we investigated the extract of a medicinal plant Pao Pereira (Pao) for its activity against pancreatic CSCs. Pao inhibited overall proliferation of human pancreatic cancer cell lines with IC50 ranging from 125 to 325 µg/mL and had limited cytotoxicity to normal epithelial cells. Pancreatic CSC population, identified using surface markers CD24+ CD44+ EpCam+ or tumor spheroid formation assay, was significantly reduced, with IC50s of ~100 µg/mL for 48 hours treatment, and ~27 µg/mL for long-term treatment. Nuclear ß-catenin levels were decreased, suggesting suppression of Wnt/ß-catenin signaling pathway. In vivo, Pao at 20 mg/kg, 5 times/week gavage, significantly reduced tumorigenicity of PANC-1 cells in immunocompromised mice, indicating inhibition of CSCs in vivo. Further investigation is warranted in using Pao as a novel treatment targeting pancreatic CSCs.