Chinese Propolis Inhibits the Proliferation of Human Gastric Cancer Cells by Inducing Apoptosis and Cell Cycle Arrest.

Special Chinese propolis sourced from the Changbai Mountains (CBMP) in Northeast China is rich in specific flavonoids and phenolic acids and its bioactivity has not been reported. This study aimed to investigate the antiproliferative effect of CBMP on cancer cells and its molecular mechanisms. Different cancer cell lines were treated with the ethanol extracts of CBMP for 24 hours before the cell viability and mechanism measurements. The results showed CBMP had weak activities against human pancreatic cancer cell PANC1, human lung cancer cell A549, human colon cancer cell HCT116, human liver cancer cell HepG2, human bladder cancer cell T24, and human breast cancer cell MDA-MB-231, but it significantly inhibited the growth of human gastric cancer SGC-7901 cells, caused cell apoptosis and cell cycle arrest in S phase, with increased production of reactive oxygen species (ROS) and reduced mitochondrial membrane potential (MMP). The results indicate that Chinese propolis sourced from the Changbai Mountains selectively inhibits the proliferation of human gastric cancer SGC-7901 cells by inducing both death receptor-induced apoptosis and mitochondria-mediated apoptosis, and cell cycle arrest in S phase. These activities and mechanisms help understand the anticancer action of propolis and its active compounds.

Royal jelly attenuates nonalcoholic fatty liver disease by inhibiting oxidative stress and regulating the expression of circadian genes in ovariectomized rats.

Nonalcoholic fatty liver disease (NAFLD) has a high incidence in postmenopausal women and is accompanied by insulin resistance, obesity, and dyslipidemia. Royal jelly (RJ), a natural substance derived from hive, possesses numerous health-beneficial properties. Here, we evaluated the effects of RJ (150, 300, and 450 mg kg-1  day-1 , 8 weeks) on NAFLD in ovariectomized (OVX) rats. Based on the results, RJ ameliorated the degree of anxiety, improved serum lipid profile, and attenuated the hepatic steatosis and liver injury in OVX rats. Furthermore, the protective effects of RJ could be attributed to its antioxidant properties, which enhance the levels of hepatic antioxidant enzymes. The qRT-PCR results also suggest that RJ improves the disturbances of circadian genes by downregulating their expression, including that of Per1 and Per 2, in the liver of OVX rats. Altogether, our findings suggest that RJ may be a promising agent for the treatment of NAFLD. PRACTICAL APPLICATIONS: Postmenopausal women are at an increased risk of NAFLD. Currently, there are no licensed therapies for NAFLD. Although hormone replacement therapy (HRT) is reported to inhibit the development of NAFLD, it causes unexpected adverse effects. As HRT is controversial, the use of natural supplements to counteract the detrimental effects of menopause has recently attracted more attention. RJ is a natural product secreted from the hypopharyngeal and mandibular glands of worker bees. The present study illustrates the protective effect of the natural product, RJ, and its underlying mechanisms on NAFLD. This is the first study to assess the effect of RJ on NAFLD under estrogen deficiency. Such findings contribute to the further utilization of RJ, which might serve as a promising therapeutic option and natural food for the treatment of NAFLD.

Mechanisms underlying the wound healing potential of propolis based on its in vitro antioxidant activity.

BACKGROUND: Propolis is a resinous substance collected by honeybees, Apis mellifera, from various plant sources. Having various pharmacological and biological activities, it has been used in folk medicine and complementary therapies since ancient times. PURPOSE: To evaluate the effects and underlying mechanism of the protective effects of the ethanol extract of Chinese propolis (EECP) on L929 cells injured by hydrogen peroxide (H2O2). STUDY DESIGN: The wound healing activities of EECP in L929 cells with H2O2-induced damage were investigated. METHODS: The main components of EECP were analyzed by RP-HPLC, and the free radical scavenging capacity and reducing power were also measured. The effects of EECP on the expression of antioxidant-related genes in fibroblast L929 cells were determined using qRT-PCR and western blotting. RESULTS: EECP had significant protective effects against cell death induced by H2O2 and significantly inhibited the decline of collagen mRNA expression caused by H2O2 in L929 cells. CONCLUSION: EECP induced the expression of antioxidant-related genes, such as HO-1, GCLM, and GCLC, which has great implications for the potential of propolis to alleviate oxidative stress in wound tissues. The protective effects of propolis have great implications for using propolis as a wound healing regent.

Identification of catechol as a new marker for detecting propolis adulteration.

Adulteration of propolis with poplar extract is a serious issue in the bee products market. The aim of this study was to identify marker compounds in adulterated propolis, and examine the transformation of chemical components from poplar buds to propolis. The chemical profiles of poplar extracts and propolis were compared, and a new marker compound, catechol, was isolated and identified from the extracts of poplar buds. The polyphenol oxidase, catechol oxidase, responsible for catalyzing oxidation of catechol was detected in poplar buds and propolis. The results indicate catechol can be used as a marker to detect propolis adulterated with poplar extract.

[Advance in studies on antioxidant activity of propolis and its molecular mechanism].

Propolis is an adhesive substance mixed with plant resins collected by honeybees (Apis mellifera) and secretions from their mandibular gland and wax gland, with wide pharmacological activity and healthcare functions. Its antioxidant activity has long been regarded as one of the most important biological activities of propolis. This article summarizes studies on the antioxidant activity of propolis extracts from different geographic origins and with different extraction methods, as well as several important monomer active ingredients in propolis, and concludes the potential molecular mechanism of antioxidant activity of propolis and its monomer ingredients, with the aim of providing ideas for further studies on pharmacological activity of propolis, as well as reference for in-depth development of propolis products.

Fast determination of royal jelly freshness by a chromogenic reaction.

UNLABELLED: Royal jelly is one of the most important products of honeybees. Given its role in development of bee brood into fertile individuals of the royal caste it is also used in health products for human consumption. Royal jelly spoils and loses its health-promoting properties depending on storage duration and conditions. To ensure product quality before selling, it is therefore necessary to assess royal jelly freshness. Many indexes of freshness have been suggested, but they all lack reliability or require complex and time-consuming analyses. Here we describe a method to detect royal jelly freshness based on a chromogenic reaction between royal jelly and HCl. We demonstrate that analyses based on color parameters allow for the discrimination of royal jelly samples based on the duration of their storage. Color parameters of royal jelly stored at -18 and 4 °C for 28 d remained comparable to that of fresh samples, which supports the reliability of the method. The method of freshness determination described is practical, cheap, and fast and can thus be used in real-time when trading royal jelly. PRACTICAL APPLICATION: The method developed can be used to assess royal jelly freshness. It is practical, cheap, and fast and can thus be used in real-time when trading royal jelly.

Therapeutic effects of propolis essential oil on anxiety of restraint-stressed mice.

Propolis has a broad spectrum of biological activities; however, whether its essential oils have neuroprotective effects is unknown. In this study, we found that propolis essential oil (PEO) could significantly reverse the anxiety-like behavior of restraint-stressed mice, and has no effect on locomotor activity. Furthermore, PEO significantly decreased the plasma levels of cortisol (CORT), adrenocorticotropic hormone (ACTH) and malondialdehyde (MDA), whereas it increased the activity of superoxide dismutase (SOD) in restraint-stressed mice. These results strongly suggest that PEO has therapeutic effects on anxiety through antagonizing the hyperfunction of hypothalamic-pituitary-adrenal (HPA) axis and improving the ability of antioxidation in brain tissue.

Protective effects of Chinese and Brazilian propolis treatment against hepatorenal lesion in diabetic rats.

Diabetes mellitus promoted an overproduction of free radicals and an increased incidence of both diabetic nephropathy and liver disease. In this report, we evaluated the effects of Chinese and Brazilian propolis on streptozotocin-induced hepatorenal injury in rats. The results demonstrated that Chinese propolis-treated rats had a 7.4% reduction in the glycated hemoglobin (HbAlc) level compared with untreated diabetic rats. Additionally, Chinese propolis induced an increase in the serum superoxide dismutase (SOD) level significantly while Brazilian propolis raised serum SOD and reduced level of malonaldehyde (MDA) and nitric synthetase (NOS). Of the measurable decrease in serum alanine transaminase (ALT), aspartate transaminase (AST) and microalbuminuria demonstrated the propolis-mediated improvement of hepatorenal function, which was further confirmed by histological examination. We also observed that Chinese and Brazilian propolis increased hepatorenal glutathione peroxidase (GSH-px) level and inhibited MDA production significantly. These results suggested that propolis may prevent hepatorenal injury by inhibiting lipid peroxidation and enhancing the activities of antioxidant enzymes.

[Study on the identification of six kinds of bee pollens by three-step infrared macro-fingerprint method].

Six kinds of bee pollens, including apricot pollen, lotus pollen, rape pollen, camellia pollen, watermelon pollen and corn poppy pollen, were identified non-destructively by Fourier transform infrared spectroscopy (FTIR) combined with derivative spectra and two-dimensional correlation spectroscopy (2D) in the present article. Compared with conventional IR spectra of samples, some certain differences were found in the characteristic peaks of proteins, lipids and carbohydrates. Obvious differences of the six kinds of bee pollens were found in the second derivative spectra. And in the 2D-IR correlation spectra, the samples presented the differences in the position and intensity of the autopeaks and correlation peak clusters. Therefore, the three-step IR macro-fingerprint provides a more rapid and effective method for the identification of different kinds of bee pollens.