Purification, structure characterization and antioxidant activity of polysaccharides from Saposhnikovia divaricata / 中国天然药物

Polysaccharide from traditional Chinese herb, Saposhnikovia divaricata (Turcz.) Schischk. (SD) was extracted, fractionated and characterized in this work. Four fractions were prepared. Their molecular weight, monosaccharide compositions, linkage modes and structural properties were characterized with SEC-MALS-RI, HPAEC-PAD, GC-MS and NMR. SDP1 was assigned as a 1, 4-α-glucan with small amount of O-6 linked branches. SDP2 contained a big amount of the 1, 4-α-glucan and a small amount of arabinogalactan, while SDP3 possessed relatively lower amount of the 1, 4-α-glucan and a big amount of the arabinogalactan. SDP4 was defined as a pectic arabinogalactan. Four fractions showed antioxidant activities in both molecular and cellular levels and their activity was ranked as SDP4 ≈ SDP3>SDP2>SDP1. The 1, 4-α-glucan in SDP1 had the weakest, while SDP3 and SDP4 showed similar and the highest antioxidant activity. The arabinogalactan was the major component of both SDP3 and SDP4, which significantly contributed to the antioxidant activity of SDP.

Pectinas de plantas medicinais: características estruturais e atividades imunomoduladoras / Pectins of medicinal plants: structural characteristics and immunomodulatory activities

RESUMO As plantas medicinais apresentam várias propriedades terapêuticas, as quais estão relacionadas com a presença de compostos bioativos. Dentre os compostos, destacam-se as pectinas, que compreendem um grupo de polissacarídeos ácidos de relevante importância medicinal e nutracêutica. As pectinas são formadas por unidades de ácido galacturônico, unidas por ligação do tipo α-(1→4), sendo classificadas em homogalacturonanas e ramnogalacturonanas tipo I (RG-I) e tipo II (RG-II). Outros polissacarídeos constituídos por arabinose e/ou galactose têm sido isolados em associação com polissacarídeos pécticos, como as arabinogalactanas (AG) (tipo I e tipo II). As AG-II podem estar associadas a proteínas, denominadas de arabinogalactana-proteínas (AGPs). Inúmeros relatos demonstram que as pectinas, bem como as AG e AGPs, podem atuar como moduladores do sistema imunológico, sendo, por isso, consideradas modificadores da resposta biológica. A imunomodulação pode estar relacionada tanto com a atividade de macrófagos quanto com as vias do sistema complemento. Em geral, os polissacarídeos provocam um estímulo da atividade fagocitária; no aumento da produção de espécies reativas de oxigênio e da secreção de citocinas pró-inflamatórias. Em relação ao sistema complemento, os polissacarídeos podem modular tanto a via clássica como a via alternativa. A presente revisão tem como objetivo principal descrever os aspectos estruturais de pectinas e suas atividades biológicas relacionadas à modulação do sistema imune. Utilizando literatura específica, estão descritas informações de 29 espécies de plantas medicinais, que apresentam como constituintes pectinas, arabinogalactanas e/ou AGPs, correlacionando suas propriedades terapêuticas com as atividades biológicas associadas ao sistema imune. Na maioria dos casos descritos na literatura, é difícil determinar como as características estruturais específicas podem estar envolvidas na modulação da atividade de macrófagos. Porém, em relação à modulação da atividade do sistema complemento fica sugerido que a presença de estruturas tipo AG-II contribuiria mais significativamente para esta atividade. Entretanto, os possíveis mecanismos de modulação de pectinas, AGs e AGPs sobre a atividade de macrófagos e/ou sobre o sistema complemento ainda não estão totalmente esclarecidos, mesmo assim, estes polímeros podem ser considerados potenciais candidatos para estudos que visam ao desenvolvimento de novos agentes terapêuticos com propriedades moduladoras benéficas para o sistema imunológico.

ABSTRACT Medicinal plants have many therapeutic properties that are related to the presence of biologically active compounds. Pectins, a group of acid polysaccharides that have relevant medicinal and nutraceutical properties, are an example of such biological compounds. Pectins contain a main chain with galacturonic acid units that are α-(1→4) linked; they can be classified into homogalacturonans and type I and type II rhamnogalacturonans (RG-I and RG-II). Other polysaccharides containing arabinose, galactose, or both have been isolated in association with pectin-type polysaccharides are known as arabinogalactans (AGs, type I and type II). Arabinogalactan-proteins (AGPs) comprise AG-II associated with proteins. Several studies have reported that pectins, as well as AG and AGPs, can act as modulators of the immune system and can therefore be considered biological response modifiers. The immunomodulation is related to the activity of macrophages as on the complement system pathways. In general, polysaccharides cause stimulation of phagocytic activity, increase production of reactive oxygen species and secretion of pro-inflammatory cytokines. Polysaccharides can modulate the classical and alternative complement pathways. The aim of this review has to describe the structural aspects of pectins and their biological activities related to the modulation of the immune system. Using literature, we reported data of 29 medicinal plant species, which present as constituents pectins, arabinogalactan and/or AGPs, correlating their therapeutic properties with biological activities associated to the immune system. In most cases described in the literature, it is difficult to determine how the specific structural characteristics can be involved in modulation of macrophage activity. However, with respect to the modulation of the activity of the complement system is proposed that the presence of AG-II-type structures would contribute most significantly to this activity. The possible mechanisms of modulation of pectins, AGs and AGPs on macrophage activity and/or the complement system are not yet fully clear, even if, these polymers can be considered potential candidates for studies aimed at the development of new therapeutic agents with modulatory properties beneficial to the immune system.

Physicochemical properties of a polysaccharide RAP-B-l from Rubus amabilis and its immunomodulating effects / 国际药学研究杂志

Objective To investigate the physicochemical properties and immunobiological activity of a polysaccharide (RAP-B-l) from stems of Rubus amabilis.

Physicochemical properties of a polysaccharide RAP-B-1 from Rubus amabilis and its immunomodulating effects / 国际药学研究杂志

Objective To investigate the physicochemica l properties and immunobiological activity of a polysaccharide (RAP-B-1) from stems of Rubus amabilis. Methods The crude polysaccharide (RAP) was obtained successively by boiling, ethanol precipitating and dialyzing. RAP was isolated with DEAE-cellulose and Sephadex G-100 to obtain a polysaccharide RAP-B-1. The physicochemical properties of RAP-B-1 were studied by hydrolysis, periodate oxidation, Smith degradation and methylation, CE, IR, NMR and GC-MS. The immunobiological activities were estimated by the proliferative activity of spleen lymphocytes and phagocytic activity of peritoneal macrophages in mice. Results The molecular weight of RAP-B-1 was 4.80×104 with specific optical rotation value [α] 20D+68.3 (c=1,H2O), and was composed of eight monosaccharides. The molar ratios were as Xyl: Ara: Glc: Rha:Gal: Man: GlcA: GalA = 1.0:6.9:0.8:1.1:6.9:0.3:0.5:3.3. RAP-B-1 was an arabinogalactan. The linkages of arabinose were →1) Ara (2,3→,→1) Ara(5→and→1) Ara, and the linkages of galactose were→1) Gal(4→,→1) Gal(6→and→1) Gal. RAP-B-1 could improve the proliferative activity of spleen T cells(P<0.05) and booste phagocytic activity of peritoneal macrophages at 50μg/ml concentration(P<0.01). Conclusion RAP-B-1 is an arabinogalactan and has immunobiological activity.