cis-Ampelopsin E, a stilbene isolated from the seeds of Paeonia suffruticosa, inhibits lipopolysaccharide-stimulated nitric oxide production in RAW 264.7 macrophages via blockade of nuclear factor-kappa B signaling pathway

Suffruticosol A elevates osteoblast differentiation targeting BMP2-Smad/1/5/8-RUNX2 in pre-osteoblasts

The Paeonia suffruticosa ANDR. (P. suffruticosa) is commonly used in traditional medicine for various purposes. Suffruticosol A (Suf-A), isolated from P. suffruticosa, is a beneficial compound with antibiofilm, antivirulence, and anti-inflammatory properties. The aim of the present study was to investigate the biological effects of Suf-A on osteogenic processes in pre-osteoblasts. It was determined here in that Suf-A (>98.02%), isolated from P. suffruticosa, showed no cytotoxicity at 0.1-30 μM; however, it induced cytotoxicity at 50-100 μM in pre-osteoblasts. Suf-A increased osteogenic alkaline phosphatase activity and expression levels of noncollagenous proteins. Adhesion and trans-migration on the extracellular matrix were potentiated by Suf-A, but not by wound-healing migration. Suf-A did not affect autophagy or necroptosis during osteoblast differentiation. We found that Suf-A increased runt-related transcription factor 2 (RUNX2) levels and mineralized matrix formation. RUNX2 expression was mediated by Suf-A-induced BMP2-Smad1/5/8 and mitogen-activated protein kinase signaling, as demonstrated by Noggin, a BMP2 inhibitor. These results suggest that Suf-A is a potential natural osteogenic compound.

Suffruticosol B Is an Osteogenic Inducer through Osteoblast Differentiation, Autophagy, Adhesion, and Migration

Suffruticosol B (Suf-B) is a stilbene found in Paeonia suffruticosa ANDR., which has been traditionally used in medicine. Stilbenes and their derivatives possess various pharmacological effects, such as anticancer, anti-inflammatory, and anti-osteoporotic activities. This study aimed to explore the bone-forming activities and mechanisms of Suf-B in pre-osteoblasts. Herein, >99.9% pure Suf-B was isolated from P. suffruticosa methanolic extracts. High concentrations of Suf-B were cytotoxic, whereas low concentrations did not affect cytotoxicity in pre-osteoblasts. Under zero levels of cytotoxicity, Suf-B exhibited bone-forming abilities by enhancing alkaline phosphatase enzyme activities, bone matrix calcification, and expression levels with non-collagenous proteins. Suf-B induces intracellular signal transduction, leading to nuclear RUNX2 expression. Suf-B-stimulated differentiation showed increases in autophagy proteins and autophagosomes, as well as enhancement of osteoblast adhesion and transmigration on the ECM. These results indicate that Suf-B has osteogenic qualities related to differentiation, autophagy, adhesion, and migration. This also suggests that Suf-B could have a therapeutic effect as a phytomedicine in skeletal disorders.

Genus Paeonia: A comprehensive review on traditional uses, phytochemistry, pharmacological activities, clinical application, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia, which comprises approximately 52 shrubs or herbaceous perennials around the world, is the only genus of the Paeoniaceae and is pervasively distributed in Asia, southern Europe, and North America. Many species of the genus Paeonia have been used for centuries in ethnomedical medical systems.

AIM OF THE REVIEW

The present study aims to summarize the traditional uses, clinical applications, and toxicology of the genus Paeonia, to critically evaluate the state-of-the-art phytochemical and pharmacological studies of this genus published between 2011 and 2020, and to suggest directions for further in-depth research on Paeonia medicinal resources.

MATERIALS AND METHODS

Popular and widely used databases such as PubMed, Scopus, Science Direct, and Google Scholar were searched using the various search strings; from these searches, a number of citations related to the traditional uses, phytochemistry, biological activities, clinical application, and toxicology of the genus Paeonia were retrieved.

RESULTS

The use of 21 species, 2 subspecies, and 7 varieties of the genus Paeonia as traditional herbal remedies has been reported, and many ethnomedicinal uses, such as the treatment of hematemesis, blood stasis, dysmenorrhea, amenorrhea, epilepsy, spasms, and gastritis, have been recorded. The roots and root bark are the most frequently reported parts of the plants used in medicinal applications. In phytochemical investigations, 451 compounds have been isolated from Paeonia plants to date, which contains monoterpenoid glucosides, flavonoids, tannins, stilbenes, triterpenoids and steroids, and phenols. Studies of their pharmacological activities have revealed the antioxidant, anti-inflammatory, antitumour, antibacterial, antiviral, cardiovascular protective, and neuroprotective properties of the genus Paeonia. In particular, some bioactive extracts and compounds (total glucosides of peony (TGP), paeonol, and paeoniflorin) have been used as therapeutic drugs or tested in clinical trials. In addition to the "incompatibility" of the combined use of "shaoyao" and Veratrum nigrum L. roots in traditional Chinese medicine theory, Paeonia was considered to have no obvious toxicity based on the available toxicological tests.

CONCLUSION

A large number of phytochemical and pharmacological reports have indicated that Paeonia is an important medicinal herb resource, and some of its traditional uses including the treatment of inflammation and cardiovascular diseases and its use as a neuroprotective agent, have been partially confirmed through modern pharmacological studies. Monoterpenoid glucosides are the main active constituents. Although many compounds have been isolated from Paeonia plants, the biological activities of only a few of these compounds (paeoniflorin, paeonol, and TGP) have been extensively investigated. Some paeoniflorin structural analogues and resveratrol oligomers have been preliminarily studied. With the exception of several species (P. suffruticosa, P. ostii, P. lactiflora, and P. emodi) that are commonly used in folk medicine, many medicinal species within the genus do not receive adequate attention. Conducting phytochemical and pharmacological experiments on these species can provide new clues that may lead to the discovery of medicinal resources. It is necessary to identify the effective phytoconstituents of crude extracts of Paeonia that displayed pharmacological activities by bioactivity-guided isolation. In addition, comprehensive plant quality control, and toxicology and pharmacokinetic studies are needed in the future studies.

Ampelopsin E Reduces the Invasiveness of the Triple Negative Breast Cancer Cell Line, MDA-MB-231

Breast cancer is the most common and the second leading cause of cancer-related deaths in women. It has two distinctive hallmarks: rapid abnormal growth and the ability to invade and metastasize. During metastasis, cancer cells are thought to form actin-rich protrusions, called invadopodia, which degrade the extracellular matrix. Current breast cancer treatments, particularly chemotherapy, comes with adverse effects like immunosuppression, resistance development and secondary tumour formation. Hence, naturally-occurring molecules claimed to be less toxic are being studied as new drug candidates. Ampelopsin E, a natural oligostilbene extracted from Dryobalanops species, has exhibited various pharmacological properties, including anticancer and anti-inflammatory activities. However, there is yet no scientific evidence of the effects of ampelopsin E towards metastasis. Scratch assay, transwell migration and invasion assays, invadopodia and gelatin degradation assays, and ELISA were used to determine the effects of ampelopsin E towards the invasiveness of MDA-MB-231 cells. Strikingly in this study, ampelopsin E was able to halt migration, transmigration and invasion in MDA-MB-231 cells by reducing formation of invadopodia and its degradation capability through significant reduction (p < 0.05) in expression levels of PDGF, MMP2, MMP9 and MMP14. In conclusion, ampelopsin E reduced the invasiveness of MDA-MB-231 cells and was proven to be a potential alternative in treating TNBC.

In vitro antitumor effects of two novel oligostilbenes, cis- and trans-suffruticosol D, isolated from Paeonia suffruticosa seeds

Naturally derived stilbenes have been shown to elicit cytotoxic, anti-steroidal, anti-mutagenic, anti-oxidative, anti-inflammatory, and antitumor bioactivities. Previous phytochemical studies revealed that the seeds of Paeonia suffruticosa are rich in natural stilbenes. In this study the antitumor effects and mechanism of action of the oligostilbene isomers, cis- and trans-suffruticosol D, isolated from the seeds of P. suffruticosa were examined. cis- and trans-suffruticosol D exhibited remarkable cytotoxicity against the human cancer cell lines A549 (lung), BT20 (breast), MCF-7 (breast), and U2OS (osteosarcoma), but showed significantly less toxicity to the normal human cell lines HMEC (breast) and HPL1A (lung). We also demonstrated that cis- and trans-suffruticosol D exerted their antitumor effects by provoking oxidative stress, stimulating apoptosis, decreasing the mitochondrial membrane potential, inhibiting cell motility, and blocking the NF-κB pathway in human lung cancer cells. In addition, we evaluated their respective bioefficacy and found that trans-suffruticosol D is more potent than cis-suffruticosol D. Collectively, our results suggest that cis- and trans-suffruticosol D could be promising chemotherapeutic agents against cancer.

Bioactive cis-stilbenoids from the tubers of Scirpus yagara

Two new cis-stilbenoids, sciryagarol I (1) and II (2) were isolated from the EtOAc extract of the tubers of Scirpus yagara, together with four known compounds. The structures of all compounds were determined by comprehensive analyses of their spectroscopic data and comparison with literature information. The compounds 3, 4 and 6 were isolated for the first time from this genus. Some compounds were tested for their cytotoxicity against human tumor cell lines and antimicrobial activity. Compounds 1-4 showed significant cytotoxicity against the Hela cell lines with IC(50) values ranging from 7.21 to 61.21μM. 1 and 2 exhibited some antimicrobial activity against Staphylococcus aureus and Candida albicans with uniform MICs of 79.3μl/ml for 2, and 152μl/ml for 1, respectively.

Ampelopsin reduces endotoxic inflammation via repressing ROS-mediated activation of PI3K/Akt/NF-κB signaling pathways

Ampelopsin (AMP), a plant flavonoid, has potent anti-inflammatory properties in vitro and in vivo. The molecular mechanisms of ampelopsin on pharmacological and biochemical actions of RAW264.7 macrophages in inflammation have not been clearly elucidated yet. In the present study, non-cytotoxic level of ampelopsin significantly inhibited the release of nitric oxide (NO) and pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α in a dose-dependent manner. Consistent with NO inhibition, ampelopsin suppressed lipopolysaccharide (LPS)-induced expression of inducible NO synthase (iNOS) by inhibiting nuclear factor κB (NF-κB) activation, which highly correlated with its inhibitory effect on IκB kinase (IKK) phosphorylation, IκB phosphorylation and NF-κB nuclear translocation. Further study demonstrated that ampelopsin suppressed LPS-induced activation of Akt without effecting mitogen-activated protein kinases (MAPKs) phosphorylation. A pharmacological inhibitor of the phosphoinositide 3-kinase (PI3K)-Akt pathway, LY294002, abrogated IKK/IκB/NF-κB-mediated iNOS gene expression. Finally, we certificated that ampelopsin reduced reactive oxygen species (ROS) accumulation and an anti-oxidant N-acetyl-L-cysteine (NAC) significantly repressed LPS-induced PI3K/Akt phosphorylation and the downstream IKK/IκB activation. NAC thereby inhibited LPS-induced iNOS expression and NO production. The present results suggest that the anti-inflammatory effect of ampelopsin is due to inhibiting the interconnected ROS/Akt/IKK/NF-κB signaling pathways.