Structural characterization and antioxidant activities of Bletilla striata polysaccharide extracted by different methods

Bletilla striata polysaccharides (BSPs) are effective for anti-inflammatory, detumescence, and radicals scavenging, with important applications in the area of food chain, pharmacy science, and health care. In this study, we comprehensively studied the interplay between the polysaccharides' formation, physicochemical properties, rheological properties, and associated antioxidant activities of BSPs from different extraction methods. The crude polysaccharides obtained from Bletilla striata by using the hot water extraction (BSPs-H), alkali-assisted extraction (BSPs-A), boiling water extraction (BSPs-B), and ultrasonic-assisted extraction (BSPs-U) methods showed different molecular weights, monosaccharide compositions, glycosidic bond compositions, and zeta potentials, but with the same IR spectra characteristic and thermal stability. By the above-mentioned four kinds of extraction methods, the resultant BSPs exhibited various degrees of reticular and lamellar structure. All the BSPs solutions exhibited shear-thinning behavior with the increase of the shear rate. Among these BSPs, BSPs-A exhibited better DPPH and ABTS radical scavenging activities and reducing power, whereas BSPs-H showed better hydroxyl radical scavenging activities.

Mechanism of Aloe Vera extract protection against UVA: shelter of lysosomal membrane avoids photodamage

Aloe Vera extract exhibited remarkable ability of reducing both in vitro and in vivo photodamage, even though it does not have anti-radical properties.

Dried-leaf Artemisia annua: A practical malaria therapeutic for developing countries?

Artemisinin from the plant Artemisia annua (A. annua) L., and used as artemisinin combination therapy (ACT), is the current best therapeutic for treating malaria, a disease that hits children and adults especially in developing countries. Traditionally, A. annua was used by the Chinese as a tea to treat “fever”. More recently, investigators have shown that tea infusions and oral consumption of the dried leaves of the plant have prophylactic and therapeutic efficacy. The presence of a complex matrix of chemicals within the leaves seems to enhance both the bioavailability and efficacy of artemisinin. Although about 1000-fold less potent than artemisinin in their antiplasmodial activity, these plant chemicals are mainly small molecules that include other artemisinic compounds, terpenes (mainly mono and sesqui), flavonoids, and polyphenolic acids. In addition, polysaccharide constituents of A. annua may enhance bioavailability of artemisinin. Rodent pharmacokinetics showed longer T_½ and T_max and greater C_max and AUC in Plasmodium chabaudi-infected mice treated with A. annua dried leaves than in healthy mice. Pharmacokinetics of deoxyartemisinin, a liver metabolite of artemisinin, was more inhibited in infected than in healthy mice. In healthy mice, artemisinin serum levels were > 40-fold greater in dried leaf fed mice than those fed with pure artemisinin. Human trial data showed that when delivered as dried leaves, 40-fold less artemisinin was required to obtain a therapeutic response compared to pure artemisinin. ACTs are still unaffordable for many malaria patients, and cost estimates for A. annua dried leaf tablet production are orders of magnitude less than for ACT, despite improvements in the production capacity. Considering that for > 2000 years this plant was used in traditional Chinese medicine for treatment of fever with no apparent appearance of artemisinin drug resistance, the evidence argues for inclusion of affordable A. annua dried leaf tablets into the arsenal of drugs to combat malaria and other artemisinin-susceptible diseases.