Suppressive Effect and Molecular Mechanism of Houttuynia cordata Thunb. Extract against Prostate Carcinogenesis and Castration-Resistant Prostate Cancer

Exploring experimental models of prostate cancer in chemoprevention: Oxidative stress as a key pathway to translational research

Prostate cancer (PCa) is the second most common cancer in men globally. Its growth is driven by oxidative stress associated with inflammation, aging, and environmental factors, including diet and lifestyle. These factors contribute to multiple stages of PCa progression, including progression to castration-resistant prostate cancer (CRPC). Therefore, oxidative stress represents an intriguing target for PCa chemoprevention and treatment. In vivo experimental models are crucial for understanding the mechanisms of PCa development, validating chemopreventive and therapeutic approaches, and translating preclinical results into clinical applications. We established a transgenic rat for adenocarcinoma of the prostate (TRAP) model, a transgenic rat that efficiently develops androgen-dependent adenocarcinoma, pathologically and biologically mimicking human PCa progression, to clarify the mechanisms of tumor progression, including the involvement of oxidative stress, and established a system for screening the chemopreventive effects of agents against PCa. Additionally, we derived a CRPC model from the TRAP model and developed a distant metastasis model, providing a comprehensive multistage rat model of prostate carcinogenesis. This review presents findings on the molecular mechanisms of PCa and the chemopreventive effects of natural compounds with antioxidant properties, such as polyphenols. We additionally described the potential for repositioning existing drugs with antiandrogenic activity for PCa chemoprevention.

Houttuynia Cordata Thunb.: A comprehensive review of traditional applications, phytochemistry, pharmacology and safety

BACKGROUND

Houttuynia Cordata Thunb. (H. cordata; Saururaceae) is a medicine food homology plant that is grown in many Asian countries. Its main phytochemical constituents are volatile oils, flavonoids, polysaccharides and alkaloids. It has considerable clinical applications and health benefits.

PURPOSE

This paper reviews the existing literatures and patents, summarizes the phytochemistry, pharmacological activity, safety and economic botanical applications of H. cordata, and provides a reference for systematic study of the pharmacological effects of H. cordata, improvement of quality standards and further development of its medicinal resources.

METHODS

A comprehensive search of literature and patents on H. cordata and its active ingredients published before June 2023 was conducted using PubMed, Google Scholar, Web of Science, and China Knowledge Network.

RESULTS

H. cordata is not only edible and medicinal but also used in various aspects of daily life such as fermented beverages, nutraceuticals, feed and cosmetics. The main phytochemical constituents of H. cordata are volatile oils, flavonoids, organic acids and alkaloids. Several in vitro and in vivo studies and clinical trials have found that H. cordata extracts possess antioxidant, anti-inflammatory, antitumor, antibacterial, hepatoprotective and renal, immunomodulatory and potent antiviral effects. The mechanisms of expression of these pharmacological effects are related to the blood-brain barrier, lipophilicity, cAMP signaling and skin permeability, including blocking the MAPK signaling pathway, inhibiting the secretion of inflammatory factors such as TNF-α and IL-1β, and activating the AMPK pathway.

CONCLUSION

This paper provides a comprehensive review of the progress of research on the traditional applications, botany, chemical composition, pharmacological effects and safety of H. cordata and discusses for the first time the economic botanical aspects, which were not explored in the previous reviews. H. cordata has a wide range of bioactive substances whose therapeutic potential has not been fully exploited, and it could provide a new non-toxic approach to many diseases. This traditional medicinal food plant should receive more attention and in-depth research in the future.

Houttuynia cordata Thunb. Hexane fraction induces MDA-MB-231 cell apoptosis via caspases, ER stress, cell cycle arrest and attenuated Akt/ERK signaling

Houttuynia cordata Thunb. (HCT) is a perennial plant used in traditional Thai medicine for many centuries. This study aimed to investigate the antiproliferative effect of the hexane fraction, which has not been explored before. HCT ethanol extract (crude extract) was sequentially fractionated to obtain a hexane (H) fraction. GC-MS was used to determine the phytochemicals. The H fraction consisted of lipids, mainly α-linolenic acid and some terpenoids. MTT assay was used to determine the cytotoxic effects of H fraction in MCF-7, MDA-MB-231, NIH3T3 and PBMCs. The mode of cell death and cell cycle analysis were determined by flow cytometry. The mechanisms of cell death were defined by mitochondrial transmembrane potential (MTP) reduction and activation of caspase-3, -8 and -9. The expression levels of the Bcl-2 family, cell cycle-related, endoplasmic reticulum (ER) stress-associated proteins; and Akt/ERK signaling molecules were investigated by immunoblotting. The H fraction was toxic to MDA-MB-231 more than MCF-7 cells but not to NIH3T3 and PBMCs. The growth of MDA-MB-231 cells was inhibited through apoptosis. MTP was disrupted whereas caspase-3, -8 and -9 were activated. The expression of pro-apoptotic Bax and Bak was upregulated, while Bid and anti-apoptotic Bcl-xL proteins were downregulated. Cyclin D1 and CDK4 levels were downregulated. The cell cycle was arrested at G1. Moreover, GRP78 and CHOP elevation indicated ER stress-mediated pathway. The expression ratio of pAkt/Akt and pERK/ERK were reduced. Taken together, the molecular mechanisms of MDA-MB-231 cell apoptosis were via intrinsic/extrinsic pathways, cell cycle arrest, ER stress and abrogation of Akt/ERK survival pathways. According to the most current research, the H fraction may be used as an adjuvant in the BC treatment; however, before the anticancer strategy can be applied to patients, it is important to determine each active compound's effects in cell lines and in vivo when compared with a combined mixture.

Qinghua decoction improves chronic nonbacterial prostatitis possibly regulating the chromogranin A/nerve growth factor/tyrosine kinase A signaling pathway mediated by inflammatory factors

OBJECTIVE

To explore the mechanism by which Qinghua decoction regulates neuroendocrine inflammation in chronic nonbacterial prostatitis (CNP) model rats and provide an experimental basis for clinical treatment.

METHODS

The rats were randomly divided into six groups: normal control, model, Qianlie Tongyu capsule, low-dose Qinghua decoction, medium-dose Qinghua decoction, and high-dose Qinghua decoction group with six rats in each group. Rats in each group were sacrificed on the 29th day of treatment, and blood and prostate tissues were collected. Serum levels of tumor necrosis factor-alpha and interleukins 1-beta, 6, 8, and 10 (TNF-α and IL-1β, -6, -8, and -10, respectively) were measured using enzyme-linked immunosorbent assay. The pathological changes in the rat prostate tissue in each group were observed under a light microscope. The expression levels of chromogranin A (CgA), nerve growth factor (NGF), and tyrosine kinase A (TrkA) were detected using reverse transcription quantitative polymerase chain reaction. Western blotting was used to detect protein expression of CgA, NGF, and TrkA.

RESULTS

In the model group, the prostate capsule membrane and stroma were significantly dilated with more inflammatory cells infiltrating the stroma and perivessels. TNF-α, IL-1β, -6, and -8, CgA, NGF, and TrkA levels increased, whereas the content of IL-10 decreased, which was statistically significant compared to that in the normal control group ( < 0.05). Prostate tissue cells in the high-dose group were neatly arranged with no obvious inflammatory cell infiltration. When compared with the model group, the high-dose Qinghua decoction group showed a significant improvement in these indices ( < 0.05).

CONCLUSION

Qinghua decoction led to inhibition of pathological changes in the prostate tissue of rats with CNP, regulation of inflammatory cytokine expression, and inhibition in the expression of CgA, NGF, and TrkA. This mechanism may be primarily related to regulation of the CgA/NGF/TrkA signaling pathway mediated by various inflammatory factors.

2-Methyl Nonyl Ketone From Houttuynia Cordata Thunb Alleviates LPS-Induced Inflammatory Response and Oxidative Stress in Bovine Mammary Epithelial Cells

Mastitis is one of the most common diseases in dairy cows, causing huge economic losses to the dairy industry every year. Houttuynia Cordata Thunb (H.cordata) is a traditional Chinese herbal medicine that is widely used in clinical treatment. However, the therapeutic effect of 2-methyl nonyl ketone (MNK), the main volatile oil component in the aqueous vapor extract of H. cordata, on mastitis has been less studied. The purpose of this study was to investigate the protective effect and mechanism of MNK against lipopolysaccharide (LPS)-induced mastitis in vitro. The results showed that MNK pretreatment of the bovine mammary epithelial cell line (MAC-T) enhanced cell viability and inhibited LPS-induced reactive oxygen species (ROS) production and inflammatory response. MNK reduced the production of pro-inflammatory cytokines such as interleukin (IL) and tumor necrosis factor-α (TNF-α) by repressing LPS-induced activation of Toll-like receptor 4-nuclear factor-κB (TLR4-NF-κB) signaling pathway. In addition, MNK protected cells from inflammatory responses by blocking the downstream signaling of inflammatory factors. MNK also induced Heme Oxygenase-1 (HO-1) production by Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway through AKT and extracellular signal-regulated kinase (ERK) pathways, thereby reducing LPS-induced oxidative damage for MAC-T cells. In conclusion, MNK played a protective role against LPS-induced cell injury. This provides a theoretical basis for the research and development of MNK as a novel therapeutic agent for mastitis.