A Novel Polysaccharide Isolated From Fresh Longan (Dimocarpus longan Lour.) Activates Macrophage via TLR2/4-Mediated PI3/AKT and MyD88/TRAF6 Pathways

A novel immunomodulatory polysaccharide (LP4) with a molecular weight 6.31 × 104 g/mol was purified from fresh longan pulp. It was composed of mannose, glucose, glucuronic acid, galactose, xylose, arabinose, galacturonic acid, fucose, and rhamnose in a molar percentage of 36:31:10:7:4:4:3:2:2, and mainly linked by (1→6)-β-Man, (1→4)-β-Glc and (1→6)-α-Glc. LP4 can obviously enhance the phagocytosis of macrophages and promote the proliferation of lymphocytes. After treating macrophages with LP4 (12.5–50 μg/ml), the production of IL-1β and TNF-α was significantly increased. These increases of cytokines were suppressed when the TLR2/TLR4 receptors were inhibited by anti-TLR2 and/or anti-TLR4 antibodies. Moreover, the mRNA expression of INOS, AKT, PI3K, TRAF6 and MyD88 was significantly suppressed by TLR2/TLR4 antibodies. These results indicated that LP4 induced macrophage activation mainly via the TLR2 and TLR4-induced PI3K/AKT and MyD88/TRAF6 pathways.

Exhaustive Plant Profile of “Dimocarpus longan Lour” with Significant Phytomedicinal Properties: A Literature Based-Review

Background: “Dimocarpus longan Lour” is a tropical and subtropical evergreen tree species mainly found in China, India, and Thailand; this plant, found naturally in Bangladesh, even locally, is used as “kaviraj” medication for treating different diseases, such as gastrointestinal disorders, wounds, fever, snake bites, menstrual problem, chickenpox, bone fractures, neurological disorders, and reproductive health. Different parts of this plant, especially juice pulp, pericarp, seeds, leaves, and flowers, contain a diverse group of botanical phytocompounds, and nutrient components which are directly related to alleviating numerous diseases. This literature-based review provides the most up-to-date data on the ethnomedicinal usages, phytochemical profiling, and bio-pharmacological effects of D. longan Lour based on published scientific articles. Methodology: A literature-based review was conducted by collecting information from various published papers in reputable journals and cited organizations. ChemDraw, a commercial software package, used to draw the chemical structure of the phytochemicals. Results: Various phytochemicals such as flavonoids, tannins, and polyphenols were collected from the various sections of the plant, and other compounds like vitamins and minerals were also obtained from this plant. As a treating agent, this plant displayed many biologicals activities, such as anti-proliferative, antioxidant, anti-cancer, anti-tyrosinase, radical scavenging activity, anti-inflammatory activity, anti-microbial, activation of osteoblast differentiation, anti-fungal, immunomodulatory, probiotic, anti-aging, anti-diabetic, obesity, neurological issues, and suppressive effect on macrophages cells. Different plant parts have displayed better activity in different disease conditions. Still, the compounds, such as gallic acid, ellagic acid, corilagin acid, quercetin, 4-O-methyl gallic acid, and (-)-epicatechin showed better activity in the biological system. Gallic acid, corilagin, and ellagic acid strongly exhibited anti-cancer activity in the HepG2, A549, and SGC 7901 cancer cell lines. Additionally, 4-O-methyl gallic acid and (-)-epicatechin have displayed outstanding antioxidant activity as well as anti-cancer activity. Conclusion: This plant species can be considered an alternative source of medication for some diseases as it contains a potential group of chemical constituents.

Eco-Friendly Rice Straw Paper Coated with Longan (Dimocarpus Longan) Peel Extract as Bio-Based and Antibacterial Packaging

This study aimed to develop active paper from rice straw fibers with its function as antibacterial activity obtained from longan (Dimocarpus longan) peels. The morphology and mechanical properties of fibers of rice straw were examined as quality parameters for paper production. Rice straw paper (RSP) with basis weight ca 106.42 g/m2, 0.34 mm thickness, 34.15% brightness, and 32.26 N·m/g tensile index was successfully prepared from fibers and pulps without chemical bleaching process. Bioactive compounds of longan peels were extracted using maceration technique with a mixture of ethanol-water, and subsequently coated onto RSP at concentration of 10%, 15% and 20% (w/v). Fourier transform infrared (FTIR) spectroscopic analysis demonstrated the functional groups of phytochemicals in the peel extract. The results of physical properties showed that the coated RSP had similar thickness and tensile index, but had lower brightness compared to control papers. Scanning electron microscopy (SEM) confirmed the significantly different of surface and cross-section structures between coated and uncoated RSP. The coated RSP had relatively greater barrier properties to prevent water absorption. In addition, the RSP coated with longan peel extracts showed significant antibacterial activity against foodborne bacteria, Staphylococcus aureus and Bacillus cereus. This study reveals the benefits of natural byproducts as potential materials for active packaging prepared by environmentally friendly processes.

Enhancement of phenolics content and biological activities of longan (Dimocarpus longan Lour.) treated with thermal and ageing process

This study is the first to compare the chemical compositions and biological activities of a conventional dried Dimocarpus longan with a novel black D. longan that underwent a thermal ageing process. Pericarp, aril, and seed of both D. longan were macerated in 95% v/v ethanol. Their chemical compositions were investigated using a Folin–Ciocalteu assay, aluminum chloride assay, and high-performance liquid chromatography. Antioxidant activities were evaluated in terms of radical scavenging and iron (III) reduction capacity. An enzyme inhibition assay was used to evaluate the hyaluronidase inhibition. Inflammatory cytokine secretion was evaluated with an enzyme-linked immunosorbent assay. After being exposed to a heating and ageing procedure, gallic acid and ellagic acid content were increased tenfold, while the corilagin content was doubled. Black D. longan seed extract was the most potent anti-hyaluronidase and antioxidant with the strongest free radical scavenging and reduction power, while black D. longan aril extract resulted in the highest inhibition of inflammatory cytokine secretion. Black D. longan contained more biologically active compounds and possessed more potent biological activities than conventional dried D. longan. Therefore, thermal ageing treatment is suggested for producing black D. longan, for which seed extract is suggested as a cosmeceutical active ingredient and aril extract for anti-inflammation.