Cardiovascular Protective Effect of Garcinia dulcis Flower Acetone Extract in 2-Kidney-1-Clip Hypertensive Rats

Morelloflavone and camboginol are bioactive compounds purified from Garcinia dulcis (GD), which has anti-inflammatory and antihypertensive properties. The objective of this study was to examine the cardiovascular protective effect of GD flower acetone extract in 2-kidney-1-clip (2K1C) hypertensive rats. Male Wistar rats underwent 2K1C or sham operation (SO) and were housed for 4 weeks. Each group of rats, then, was further divided into 2 subgroups receiving oral administration of either 50 mg/kg BW GD extract or corn oil (vehicle) daily for 4 weeks. Noninvasive blood pressure (BP) and body weight were measured weekly throughout the study. Subsequently, the invasive measurement of arterial BP and the heart rate were determined in all anesthetized rats. The baroreceptor reflex sensitivity (BRS) was investigated by injection of either phenylephrine or sodium nitroprusside for bradycardia or tachycardia response, respectively. Histological examination of the heart and thoracic aorta was also performed in order to investigate the general morphology and the tumor necrosis factor alpha (TNF-α) expression. We found that the GD flower extract significantly diminished the BP and restored the impaired BRS. Moreover, it also decreased the TNF-α expression in the cardiac muscle and thoracic aorta of 2K1C when compared to the SO group. Taken together, our data showed that GD flower extract exhibits the cardiovascular protective effect in the 2K1C hypertensive rats.

Phytochemistry and pharmacology of natural prenylated flavonoids

Prenylated flavonoids are a special kind of flavonoid derivative possessing one or more prenyl groups in the parent nucleus of the flavonoid. The presence of the prenyl side chain enriched the structural diversity of flavonoids and increased their bioactivity and bioavailability. Prenylated flavonoids show a wide range of biological activities, such as anti-cancer, anti-inflammatory, neuroprotective, anti-diabetic, anti-obesity, cardioprotective effects, and anti-osteoclastogenic activities. In recent years, many compounds with significant activity have been discovered with the continuous excavation of the medicinal value of prenylated flavonoids, and have attracted the extensive attention of pharmacologists. This review summarizes recent progress on research into natural active prenylated flavonoids to promote new discoveries of their medicinal value.

Camboginol and Morelloflavone from Garcinia dulcis (Roxb.) Kurz Flower Extract Promote Autophagic Cell Death against Human Glioblastoma Cells through Endoplasmic Reticulum Stress

Garcinia dulcis is a tropical plant native to Southeast Asia that is traditionally used as a folk remedy to cure several pathological symptoms. Camboginol and morelloflavone have been revealed by previous studies as the principal bioactive compounds from the flower extract of G. dulcis. The disease-preventing properties of camboginol or morelloflavone, including anti-cancer, from various parts of G. dulcis have been revealed by recent studies. Glioblastoma is the aggressive malignant stage of brain cancer and suffers from chemotherapeutic resistance. This study aimed to test the anti-cancer effect of G. dulcis flower extract against the proliferation of A172 human glioblastoma cells. The extract had cytotoxic activity and promoted cell cycle arrest at the S and G2/M phases. Autophagic cell death was promoted by cytotoxic concentrations of the extract, as observed by enhancing autophagic flux and the expression of autophagic markers. Autophagic cell death induced by the extract might be associated with endoplasmic reticulum (ER) stress. Conclusively, it was indicated by this study that the extract from the flower of G. dulcis had a protective effect against the proliferation of A172 human glioblastoma cells through the induction of ER stress-mediated cytotoxic autophagy.

CONJUGATION WITH SILVER NANOPARTICLES ENHANCES ANTI-ACANTHAMOEBIC ACTIVITY OF KAPPAPHYCUS ALVAREZII

Nanomedicine has the potential in enhancing the efficacy and bioavailability of anti-infective agents. Here we determined whether conjugation of the Malaysian cultivated seaweed Kappaphycus alvarezii with silver-conjugated nanoparticles enhanced anti-acanthamoebic properties. Silver-conjugated K. alvarezii were successfully synthesized, followed by characterization with Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, and transmission electron microscopy. Amoebicidal effects were evaluated against Acanthamoeba castellanii, and cytotoxicity assays were performed using HaCaT cells. Viability assays revealed that silver nanoparticles conjugated with K. alvarezii extract exhibited significant antiamoebic properties (P < 0.05). Nano-conjugates induced the production of reactive oxygen species. Importantly, silver-conjugated extract inhibited amoeba-mediated host cell damage as established by lactate dehydrogenase release. Neither the nano-conjugates nor the extract showed cytotoxicity against human cells in vitro. Liquid chromatography and mass spectroscopy revealed several molecules, including 2,6-nonadien-1-ol, N-desmethyl trifluoperazine, dulciol B, lucidumol A, acetoxolone, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, C16 sphinganine, 22-tricosenoic acid, and β-dihydrorotenone, of which dulciol B and C16 sphinganine are known to possess antimicrobial activities. In summary, marine organisms are an important source of bioactive molecules with anti-acanthamoebic properties that can be enhanced by conjugating with silver nanoparticles. Natural products combined with nanotechnology using multifunctional nanoparticle complexes can deliver therapeutic agents effectively and hold promise in the development of new formulations of anti-acanthamoebic agents.

Revalorization of bioactive compounds from tropical fruit by-products and industrial applications by means of sustainable approaches

Tropical fruits trade is on the rise due to the claimed health benefits related with their consumption. Functional activities are exerted by the presence of bioactive compounds which could be used for prevention or amelioration diseases. However, the occurrence of bioactive compounds is found mainly in non-edible fraction of tropical fruits which are usually discarded. Therefore, the revalorization of tropical fruits by-products as source of functional compounds is on the cutting-edge research. The implementation of this challenge not only allows the enhancement of the tropical fruits by-products management, but also the production of value-added products. This review compiles the latest comprehensive information about the revalorization of bioactive compounds from tropical fruits by-products. A revision of the sustainable green technologies used for the isolation of valuable compounds has been carried out as well as the current food, functional, cosmeceutical and bioenergetics industrial applications of bioactive compounds extracted from tropical fruits by-products.

Physiological and Metabolic Effects of Yellow Mangosteen (Garcinia dulcis) Rind in Rats with Diet-Induced Metabolic Syndrome

Metabolic syndrome is a cluster of disorders that increase the risk of cardiovascular disease and diabetes. This study has investigated the responses to rind of yellow mangosteen (Garcinia dulcis), usually discarded as waste, in a rat model of human metabolic syndrome. The rind contains higher concentrations of phytochemicals (such as garcinol, morelloflavone and citric acid) than the pulp. Male Wistar rats aged 8-9 weeks were fed either corn starch diet or high-carbohydrate, high-fat diet for 16 weeks, which were supplemented with 5% freeze-dried G. dulcis fruit rind powder during the last 8 weeks. We characterised metabolic, cardiovascular, liver and gut microbiota parameters. High-carbohydrate, high-fat diet-fed rats developed abdominal obesity, hypertension, increased left ventricular diastolic stiffness, decreased glucose tolerance, fatty liver and reduced Bacteroidia with increased Clostridia in the colonic microbiota. G. dulcis fruit rind powder attenuated these changes, improved cardiovascular and liver structure and function, and attenuated changes in colonic microbiota. G. dulcis fruit rind powder may be effective in metabolic syndrome by appetite suppression, inhibition of inflammatory processes and increased fat metabolism, possibly related to changes in the colonic microbiota. Hence, we propose the use of G. dulcis fruit rind as a functional food to ameliorate symptoms of metabolic syndrome.