Isolation and characterization of an anti-complementary polysaccharide D3-S1 from the roots of Bupleurum smithii

Fulvanines J-K, two rare lactam pyrrole alkaloids from Hemerocallis fulva

Two rare jatropham lactam derivatives, named as fulvanines J-K (1-2), together with six known pyrrole alkaloids, 5,5'-oxydi(3-methyl-3-pyrrolin-2-one) (3), (-)-5-hydroxy-3-methyl-3-pyrrolin-2-one (jatropham) (4), (±)-5-O-methyljatropham (5), perlolyrine (6), butyl-2-formyl-5-(hydroxymethyl)-1H-pyrrole-1-butanoate (7), and hemerocallisamine II (8), were isolated from the flower of Hemerocallis fulva. Their structures were elucidated on the basis of spectroscopic methods and compared with the NMR spectra data in the literature. All compounds were evaluated for their anti-complementary activity in vitro, and compounds 1, 4, and 6 exhibited anti-complement effect with CH50 values from 0.61 to 1.42 mM.

Structural Characterization and Anti-inflammatory Activities of Anticomplementary Polysaccharides from Rhododendron principis

Rhododendron principis leaves have been used as "Dama", a Traditional Tibetan Medicine for treating inflammatory diseases. R. principis crude polysaccharides with anticomplementary activity demonstrated promising anti-inflammatory effects on acute lung injury induced by lipopolysaccharide. R. principis crude polysaccharides significantly decreased the levels of TNF-α and interleukin-6 in both serum and blood and bronchoalveolar lavage fluid in lipopolysaccharide-induced acute lung injury mice by intragastric administration (100 mg/kg). A heteropolysaccharide, ZNDHP, was obtained from R. principis crude polysaccharides with successive anticomplementary activity-guided separation. ZNDHP was characterized as a branched neutral polysaccharide with a backbone composed of → 2)-β-Glcp-(1→, → 2,6)-α-Glcp-(1→, → 6,3)-β-Galp-(1→, → 2,6)-α-Galp-(1→, → 6,2)-β-Glcp-(1→, → 4)-α-Glcp-(1→, → 5)-β-Araf-(1→, → 3,5)-α-Araf-(1→, and → 4,6)-β-Manp-(1→, and the backbone structure was further confirmed by partial acid hydrolysis. In addition to anticomplementary and antioxidant activities, ZNDHP exhibited potent anti-inflammatory activity by significantly inhibiting the secretion of nitric oxide, TNF-α, interleukin-6, and interleukin-1β of lipopolysaccharide-treated RAW 264.7 cells. However, all of these activities decreased greatly after partially hydrolyzing, indicating the importance of the multibranched structure for its bioactivity. Therefore, ZNDHP might be an important component of R. principis for treating inflammation.

Extraction, purification, structure characteristics, biological activities and pharmaceutical application of Bupleuri Radix Polysaccharide: A review

Bupleuri Radix (BR), as a well-known plant medicine of relieving exterior syndrome, has a long history of usage in China. Bupleuri Radix Polysaccharide (BRP), as the main component and an important bioactive substance of BR, has a variety of pharmacological activities, including immunoregulation, antioxidant, antitumor, anti-diabetic and anti-aging, etc. In this review, the advancements on extraction, purification, structure characteristics, biological activities and pharmaceutical application of BRP from different sources (Bupleurum chinense DC., Bupleurum scorzonerifolium Willd., Bupleurum falcatum L. and Bupleurum smithii Woiff. var. Parvifolium Shan et Y. Li.) are summarized. Meanwhile, this review makes an in-depth discussion on the shortcomings of the research on BRP, and new valuable insights for the future researches of BRP are proposed.

Cynasibirolide A, One New Humulanolide Sesquiterpene from Cynanchum acutum subsp. sibiricum

Cynasibirolide A (1), one new humulanolide sesquiterpene, together with four known analogs, asteriscanolide (2), (1S,8S)-8-hydroxyhumula-2Z,6E,9E-trien-1,12-olide (3), (1S,7R)-8-oxohumula-2Z,9E-dien-1,12-olide (4), and (+)-6,7,9,10-tetrahydroasteriscunolide (5) were isolated from the roots and rhizomes of Cynanchum acutum subsp. sibiricum. Their structures and configurations were elucidated by spectroscopic methods, including 2D-NMR techniques, and the structure of 1 was confirmed by single-crystal X-ray diffraction. All compounds were evaluated for their anti-complementary activity in vitro, and compound 3 exhibited anti-complement effect with CH₅₀ value of 0.45 mM.

Development of Broad-Spectrum Antiviral Agents-Inspiration from Immunomodulatory Natural Products

Developing broad-spectrum antiviral drugs remains an important issue as viral infections continue to threaten public health. Host-directed therapy is a method that focuses on potential targets in host cells or the body, instead of viral proteins. Its antiviral effects are achieved by disturbing the life cycles of pathogens or modulating immunity. In this review, we focus on the development of broad-spectrum antiviral drugs that enhance the immune response. Some natural products present antiviral effects mediated by enhancing immunity, and their structures and mechanisms are summarized here. Natural products with immunomodulatory effects are also discussed, although their antiviral effects remain unknown. Given the power of immunity and the feasibility of host-directed therapy, we argue that both of these categories of natural products provide clues that may be beneficial for the discovery of broad-spectrum antiviral drugs.

Structural characteristics and anti-complement activities of polysaccharides from Sargassum hemiphyllum

Three polysaccharides (SH-1, SH-2 and SH-3) were purified from a brown macroalgea, Sargassum hemiphyllum. The autohydrolysis products from each polysaccharide were separated to three fractions (S fractions as oligomers, L fractions as low molecular weight polysaccharides and H fractions as high molecular weight polysaccharides). Mass spectroscopy of S fractions (SH-1-S, SH-2-S and SH-3-S) showed that these three polymers all contained short stretches of sulfated fucose. The structures of L fractions (SH-1-L, SH-2-L and SH-3-L) were determined by nuclear magnetic resonance (NMR). SH-1-L was composed of two units, unit A (sulfated galactofucan) and unit B (sulfated xylo-glucuronomannan). Unit A contained a backbone of (1, 6-linked β-D-Gal) n1, (1, 3-linked 4-sulfated α-L-Fuc) n2, (1, 3-linked 2, 4-di-sulfated α-L-Fuc) n3, (1, 4-linked α-L-Fuc) n4 and (1, 3-linked β-D-Gal) n5, accompanied by some branches, such as sulfated fuco-oligomers, sulfated galacto-oligomers or sulfated galacto-fuco-oligomers. And unit B consisted of alternating 1, 4-linked β-D-glucuronic acid (GlcA) and 1, 2-linked α-D-mannose (Man) with the Man residues randomly sulfated at C6 or branched with xylose (Xyl) at C3. Both SH-2-L and SH-3-L were composed of unit A and their difference was attributed to the ratio of n1: n2: n3: n4: n5. Based on monosaccharide analysis, we hypothesize that both SH-1-H and SH-2-H contained unit A and unit B while SH-3-H had a structure similar to SH-3-L. An assessment of anti-complement activities showed that the sulfated galactofucan had higher activities than sulfated galacto-fuco-xylo-glucuronomannan. These results suggest that the sulfated galactofucans might be a good candidate for anti-complement drugs.

Multi-omics reveals the mechanisms of antidepressant-like effects of the low polarity fraction of Bupleuri Radix

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Bupleuri (Bupleurum chinense DC.) is a traditional Chinese medicine that has the effect of soothing the liver and relieving depression, and widely used in the field of antidepression.

AIM OF THE STUDY

The low polarity fraction of Bupleuri Radix (PBR) has proved to be effective for the treatment of depression based on the results of our previous study. However, mechanisms of definite antidepressant-like effects remained unclear. The purpose of this study is to reveal mechanisms of antidepressant-like effects of PBR with multi-dimensional omics.

MATERIALS AND METHODS

LC-MS metabolomics combined with 16S rRNA gene sequencing were used to investigate the effects of PBR on gut microbiota and metabolites in CUMS-induced depression, and Pearson correlation analysis was carried out on gut microbiota and metabolites.

RESULTS

PBR significantly improved depression-like behaviors in the CUMS model rats. Moreover, PBR significantly increased the levels of BDNF in the hippocampus. Cecum contents metabolomics revealed that 16 biomarkers associated with PBR antidepressant effect were screened, which were involved 3 metabolic pathways including primary bile acid biosynthesis, taurine and hypotaurine metabolism, glyoxylate and dicarboxylate metabolism. Gut microbiota further analysis demonstrated that PBR increased the diversity of gut microbiota, and significantly inhibited the growth of [Prevotella] and Ochrobactrum. Furthermore, Pearson analysis revealed there was a strong correlation between cecum contents of metabolites and gut microbiota.

CONCLUSIONS

PBR improved depression-like behavior by regulating metabolic profiles and gut microbiota, and contributing to further understand the entailed antidepressant-like mechanisms of PBR.

Bupleurum polysaccharides ameliorated renal injury in diabetic mice associated with suppression of HMGB1-TLR4 signaling

Bupleurum polysaccharides (BPs) is isolated from Bupleurum smithii var. parvifolium, a key traditional Chinese medicine. The study was to investigate the effects of BPs on diabetic kidney injury. After two intraperitoneal injections of streptozotozin (STZ) 100 mg·kg^-1, renal injury in diabetic mice was induced and BPs was orally administrated at dosages of 30 and 60 mg·kg^-1·d^-1. The STZ injected mice developed renal function damage, renal inflammation and fibrosis known as diabetic kidney disease (DKD). BPs significantly reduced serum creatinine level and urinary albumin excretion rate, with the attenuated swelling of kidneys. BPs treatment obviously alleviated the pathological damage of renal tissue. The progression of renal injury in BPs treated mice was inhibited with less expression of type IV collagen (Col IV), fibronectin (FN) and α-smooth muscle actin (α-SMA). The inhibition of inflammation in kidney was associated with the reduced level of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). BPs administration suppressed the over-expression of toll like receptor 4 (TLR4) and high-mobility group box 1 (HMGB1) with lowered activity of nuclear factor kappa B (NF-κB) in renal tissue of diabetic mice. Oral administration of BPs effectively prevented the development ofrenal injury in diabetic mice. This study suggested that the protection provided by BPs might affect through the interruption of HMGB1-TLR4 pathway, leading to the inhibition of renal inflammation and fibrotic process.

Herbs as thermoregulatory agents in poultry: An overview

The adverse effect of increased environmental temperature during summer season on avian industry has received great global concern. High temperature leads to severe economic loss in poultry production, because it is considered as valuable stress factor. Several practical methods were used to alleviate the adverse impact of increased temperature; among them were dietary modifications. So, several types of herbs are supplemented to reduce the deleterious influences of thermal stress altitudes in various animals, and even to prevent their adverse impacts. Therefore, sustainable supports for dietary modification based on herbs supplementations are largely needed, particularly when consider the additional advantages of herbs such as availability, actual efficiency, low cost, as well as their free from residual impact and antibiotic resistance. Numerous types of herbs were concluded to their efficient properties by poultry breeders to overcome a variety of the harmful effects of high ambient temperature. The present article deliberates the different practical applications of several members of the traditional herbal wealth to improve the general health state of poultry particularly as thermoregulatory and immunomodulatory agents, and for countering the heat stress-associated immunosuppressive effects. Additionally, the antioxidant activity of herbal growth promoters and their influence on improvement of production performances were a special aim of this review. The reported information will be helpful for improvement of general production and health status of birds reared under the heat stress via enhancement of immune response and stress tolerance, and popularizes usage of herbs amongst poultry producers.

Structural characterization and anticomplement activities of three acidic homogeneous polysaccharides from Artemisia annua

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. is a heat-clearing Chinese medicine and well-known for its antimalarial constituent, artemisinin. It has gained increasing attention for its anti-inflammatory and immunoregulatory activities. Interestingly, the crude polysaccahrides of A. annua exhibited potent anticomplement activity. This study was to isolate and characterize its anticomplement homogeneous polysaccharides from A. annua, and reveal the relationship between structures and anticomplement activities of the isolated polysaccharides.

MATERIALS AND METHODS

Water-soluble crude polysaccharides from the aerial parts of A. annua were extracted and fractionated by DEAE-cellulose and Sephacryl S-300 gel permeation chromatography. Homogeneity, molecular weight, monosaccharide composition, methylation and NMR analysis were performed to characterize the structures of homogeneous polysaccharides. Their anticomplement activities and targeting components in the complement activation cascade were evaluated by hemolytic assays.

RESULTS

Three homogeneous polysaccharides (AAP01-1, AAP01-2 and AAP01-3) were obtained from A. annua. AAP01-1 was composed of seven monosaccharides, including mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose. AAP01-2 and AAP01-3 had similar monosaccharides with AAP01-1, except the absence of glucuronic acid. They were all branched acidic heteropolysaccharides with different contents of galacturonic acid (8%, 28% and 15% for AAP01-1, AAP01-2 and AAP01-3, respectively). AAP01-2 showed potent anticomplement activity with CH₅₀ value of 0.360 ± 0.020 mg/mL through the classical pathway and AP₅₀ value of 0.547 ± 0.033 mg/mL through the alternative pathway. AAP01-3 exhibited slightly weaker activity (CH₅₀: 1.120 ± 0.052 mg/mL, AP₅₀: 1.283 ± 0.061 mg/mL), while AAP01-1 was inactive. Moreover, AAP01-2 acted on C1q, C3, C4, C5 and C9 components and AAP01-3 interacted with C3, C4 and C5 components in the activation cascade of complement system.

CONCLUSION

These results indicated that the relatively high contents of galacturonic acid were important for anticomplement activities of the polysaccharides from A. annua. The anticomplement polysaccharides are another kind of bioactive constituents conferring heat-clearing effects of A. annua.

A new abietane diterpene and anti-complementary constituents from Juniperus tibetica

Anti-complementary activity-guided fractionation led to the isolation of a new abietane diterpene (1) and twenty-five known compounds (2-26) from the twigs and leaves of Juniperus tibetica. All the compounds were isolated from J. tibetica for the first time. The structure of 1 was assigned by spectroscopic data and X-ray crystallography analysis. Five lignans (2, 3, 7, 9 and 10), two flavones (19 and 22), and one coumarin (23) exhibited anti-complementary activity with CH₅₀ values ranging from 0.3 to 3.69 mM.

Structural characterization and anticomplement activity of an acidic polysaccharide from Hedyotis diffusa

An acidic homogeneous polysaccharide (HD-PS-1) was purified from Hedyotis diffusa (Willd.) Roxb. HD-PS-1 possessed a backbone chain of →[4)-β-Glcp-3-OAc-(1]₆→[6)-β-Manp-(1]₂→6)-α-Galp-(1→[4)-α-Galp-(1]₂→, with three branches of β-Manp-(1→3)-β-GlcpA, α-Rhap-(1→3)-α-Rhap and α-Galp attached to the backbone chain at O-4 position of 1,4,6-linked β-Manp, O-3 position of 1,3,6-linked α-Galp and O-3 position of 1,3,4-linked α-Galp, respectively. HD-PS-1 exhibited significant anticomplement activity (CH₅₀: 0.084 ± 0.009 mg/mL, AP₅₀: 0.176 ± 0.013 mg/mL). It was found that the presence of uronic acids is important to anticomplement activity of HD-PS-1, given that the reduced HD-PS-1 showed weaker activity (CH₅₀: 0.456 ± 0.008 mg/mL, AP₅₀: 0.572 ± 0.010 mg/mL). Preliminary mechanism study indicated that HD-PS-1 interacted with C3 and C4 in the complement activation cascade. In addition, a neutral homogeneous polysaccharide (HD-PS-2) was also purified and characterized. HD-PS-2 displayed antioxidant activity by scavenging DPPH· radicals without anticomplement activity.

A new monoterpene glycoside from Pedicularis verticillata and anticomplementary activity of its compounds

A new monoterpene glycoside named as pedivertoside D (1), together with 13 known compounds (2-14, resp.) were isolated from the whole plant of Pedicularis verticillata L. The new compound was identified as (2E,6E,5R)-5,8-dihydrooxy-2,6-dimethyl-3,7-octadienyl-β-D-glucopyranoside by spectroscopic methods including 2 D-NMR techniques. The known compounds were determined spectroscopically and compared with previously reported spectral data. Compounds 6 and 9 exhibited anticomplementary effects against the classical pathway (CP) with CH₅₀ values of 0.07 mM and 0.23 mM, respectively, which are plausible candidates for developing potent anti-complementary agents from this plant.

Polysaccharides extracted from the roots of Bupleurum chinense DC modulates macrophage functions

The present study aimed to investigate the effects of polysaccharides extracted from Bupleurum chinense DC (BCPs) on macrophage functions. In the in vivo experiment, 1 mL of 5% sodium thioglycollate was injected into the abdomen of the mice on Day 0 and macrophages were harvested on Day 4. The macrophages were cultured in plates and treated with different concentrations of BCPs and stimulus. Effects of BCPs on macrophage functions were assessed by chemotaxis assay, phagocytosis assay and Enzyme-Linked Immunosorbent Assay (ELISA). Our results showed the enhanced chemotaxis, phagocytosis and secretion of nitric oxide (NO) and inflammatory cytokines by macrophages when treated with BCPs. However, when chemotaxis and phagocytosis were up-regulated by complement components or opsonized particles, BCPs inhibited these effects. Also, the NO production induced by lipopolysaccharides (LPS) was suppressed by BCPs mildly. Moreover, BCPs had an inhibitory effect on the [Ca²⁺]_i elevation of macrophages. These results suggested that BCPs exerted modulatory effects on macrophage functions, which may contribute to developing novel approaches to treating inflammatory diseases.

A novel dimeric flavonol glycoside from Cynanchum acutum subsp. sibiricum

A novel dimeric flavonol glycoside, Cynanflavoside A (1), together with six analogues, kaempferol-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (2), quercetin-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (3), kaempferol-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (4), quercetin-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (5), kaempferol-3-O-β-D-glucopyranosyl-7-O-α-L-rhamnopyranoside (6), and quercetin-3-O-galactoside (7) were isolated from the n-butyl alcohol extract of Cynanchum acutum subsp. sibiricum. Their structures were determined spectroscopically and compared with previously reported spectral data. All compounds were evaluated for their anti-complementary activity in vitro, and only compound 5 exhibited anti-complement effects with CH₅₀ value of 0.33 mM.

Iridoids from Pedicularis verticillata and Their Anti-Complementary Activity

Three new iridoids named as pediverticilatasin A - C (1 - 3, resp.), together with five known iridoids (4 - 8, resp.) were isolated from the whole plants of Pedicularis verticillata. The structures of three new compounds were identified as (1S,7R)-1-ethoxy-1,5,6,7-tetrahydro-7-hydroxy-7-methylcyclopenta[c]pyran-4(3H)-one (1), (1S,4aS,7R,7aS)-1-ethoxy-1,4a,5,6,7,7a-hexahydro-7-hydroxy-7-methylcyclopenta[c]pyran-4-carboxylic acid (2), (1S,4aS,7R,7aS)-1-ethoxy-1,4a,5,6,7,7a-hexahydro-7-hydroxy-7-methylcyclopenta[c]pyran-4-carbaldehyde (3). Their structures were elucidated on the basis of spectroscopic methods and compared with the NMR spectra data in the literature. All compounds were evaluated for their anti-complementary activity on the classical pathway of the complement system in vitro. Among which, compounds 1, 3, and 6 exhibited anti-complementary effects with CH₅₀ values ranging from 0.43 to 1.72 mm, which are plausible candidates for developing potent anti-complementary agents.

Ultrasound-assisted Extraction of Polysaccharide from Radix Bupleuri using Response Surface Methodology and Antioxidant Research of the Polysaccharide

This report used Response Surface Methodology (RSM) to analyze the conditions that extracting polysaccharide compound from Radix Bupleuri using ultrasonic wave. For determining the optimal extraction conditions, four independent variables, temperature (°C), ultrasonic intensity (UI, W/cm2), dilution rate (water-material ratio, mL/g) and time (min), were investigated using Box-Behnken design. In the results, the best condition after optimization was dilution rate of 35.0:1, UI of 24.5 W/cm2, temperature of 69.5°C and time of 14.6 min. Extraction efficiency was 7.67% and the purity reached 44.14%. It illustrates that the ultrasound-assisted extraction (UAE) was efficient and suitable for extracting polysaccharide from Radix Bupleuri. This paper also investigated the antioxidant activity of Radix Bupleuri polysaccharide (RBP) on superoxide anion radical, hydroxyl radical, and 2,2-diphenyl-1-picry-hydrazyl (DPPH), in vitro experiment. The result indicated that RBP could remarkably sweep away the hydroxyl radical, and had the capacity for clearing away superoxide radical and DPPH.

Polysaccharides from Sargassum thunbergii: Monthly variations and anti-complement and anti-tumour activities

Monthly variations of polysaccharides from Sargassum thunbergii and their anti-complement and anti-tumour activities were investigated. It was observed that an increase in fucose and total sugar contents occurred during the growth period (from early April to mid-June), accompanied by a decrease in molar ratios of other monosaccharides to fucose. The highest yields were obtained from early July to early September, which was in accordance with the significant increase in molar ratio of glucose to fucose and decrease in molar ratio of other monosaccharides to fucose. And the above results suggested that S. Thunbergii synthesized large amount of laminaran, the storage substance of brown algae, during the senescence period. However, sulfate contents were relatively stable in the life cycle of S. thunbergii. These results suggested that S. thunbergii synthesized complex sulfated heteropolysacchairdes during inactive period, while during other periods, it synthesized more sulfated galactofucan. All polysaccharides showed anti-complement activity, suggesting that the harvesting time did not influence the anti-complement activities. In the anti-tumour assay in vitro, the polysaccharides taken during the senescence period had much lower anti-tumour activity, suggesting that fucoidan, but not laminaran, determined the anti-tumour activities. Therefore, polysaccharides from S. thunbergii might have great potential in anti-complement and anti-tumour application.

The structure-activity relationship between polysaccharides from Sargassum thunbergii and anti-tumor activity

Polysaccharides derived from Sargassum thunbergii were prepared to investigate the structure-activity relationship between polysaccharides and anti-tumor activity in vitro. Many factors were examined. Overall, STW (polysaccharide extracted by hot water) had the best activity, followed by STJ (polysaccharide extracted by dilute alkali), and then STA (polysaccharide extracted by dilute acid). Location of algae had no effect at 500μg/mL and 1000μg/mL, while STW-QD (algae collected from Qingdao, China) had the best activity, followed by STW-WZ (algae collected from Wenzhou, China) and STW-LJ (algae collected from Lianjiang, China) and then STW-DL (algae collected from Dalian, China) and STW-RC (algae collected from Rongcheng, China) at 250μg/mL. Moreover, molecular weight had no effect at 1000μg/mL, while higher molecular weights were associated with better activities at 250μg/mL and 500μg/mL. Sulfate content had no effect at 1000μg/mL, while anti-tumor activities decreased accompanying with the changes of sulfate content. Uronic acid content was an important factor influencing activity. The fractions of STW showed little anti-tumor activity; however, the mixture of the fractions of STW showed approximately 60% inhibition. Overall, these findings suggested that the anti-tumor activity of polysaccharides required multilateral cooperation and that some of the effective components were lost.

Immune enhancement effects and extraction optimization of polysaccharides from Citrus aurantium L. var. amara Engl

The crude polysaccharides ofCitrus aurantiumL. var.amaraEngl (CAVAPs) were extracted and their bioactivities including DPPH radical scavenging activity, cytotoxicity to human breast cancer cells, MCF-7, as well as lung cancer cells, HCC827, and their immune-enhancement activity were evaluated.

Structure characterization of two novel polysaccharides isolated from the spikes of Prunella vulgaris and their anticomplement activities

ETHNOPHARMACOLOGICAL RELEVANCE

The spikes of Prunella vulgaris have long been used as a traditional Chinese medicine to treat various inflammation-related diseases. The aim of this study was to isolate and characterize homogenous polysaccharides from this herb and to evaluate their anticomplement activity.

MATERIALS AND METHODS

Anticomplement activity-guided fractionation of the hot water extract of P. vulgaris was performed by DEAE-cellulose and size-exclusion chromatography, yielding two homogeneous polysaccharides PW-PS1 and PW-PS2. The homogeneity, molecular weight, monosaccharide composition and linkage of the two polysaccharides were determined in addition to other chemical characterizations. The anticomplement activity of the polysaccharides was evaluated and expressed as 50% hemolytic inhibition concentration through the classical pathway (CH₅₀ value) and alternative pathway (AP₅₀ value). The preliminary mechanism for the complement activation cascade was also assessed.

RESULTS

PW-PS1 and PW-PS2 were both branched acidic polysaccharides. PW-PS1 was composed of Ara, Xyl, and 4-methoxy-Glc A in a ratio of 1.0: 2.6: 0.8. The main linkages of the sugar residues of PW-PS1 included terminal β-d-Xylp, 1,4-linked β-d-Xylp, 1,3-linked α-d-Arap, 1,3,5-linked α-d-Arap, and terminal 4-methoxy-α-d-Glcp A. PW-PS2 was composed of Rha, Ara, Xyl, Gal, and Gal A in a ratio of 0.6: 1.0: 1.3: 1.8: 3.4. The main linkages between the sugar residues of PW-PS2 included terminal Araf, 1,4-linked β-d-Xylp, 1,3-linked α-d-Rhap, terminal α-d-Galp, and 1,4,6-linked α-d-Galp. PW-PS1 and PW-PS2 inhibited complement activation through both the classical and alternative pathways with CH₅₀ values of 0.28 and 0.13mg/mL, respectively, and AP₅₀ values of 0.40 and 0.35mg/mL, respectively. Preliminary mechanism studies using complement component-depleted sera showed that PW-PS1 acted on the C1q, C3, and C9 components and that PW-PS2 acted on the C1q, C2, C3, C5, and C9 components.

CONCLUSION

Our study suggested that PW-PS1 and PW-PS2 could be valuable for the treatment of diseases associated with the excessive activation of the complement system.

Anti-Complementary Components of Helicteres angustifolia

A first phenalenon derivative with an acetyl side chain at C-8, 8-acetyl-9-hydroxy-3-methoxy-7-methyl-1-phenalenon (compound 1), and a pair of new sesquilignan epimers at C-7″ of hedyotol C and hedyotol D analogs, hedyotol C 7″-O-β-d-glucopyranoside (compound 2) and hedyotol D 7″-O-β-d-glucopyranoside (compound 3) were isolated from the aerial parts of Helicteres angustifolia together with nine known compounds (4–12). Their structures were elucidated on the basis of spectroscopic methods, including mass spectroscopy, and 1D and 2D nuclear magnetic resonance. Eleven isolates exhibited anti-complementary activity. In particular, compounds 4 and 5 exhibited potent anti-complementary activities against the classical and alternative pathways with CH₅₀ values of 0.040 ± 0.009 and 0.009 ± 0.002 mM, and AP₅₀ values of 0.105 ± 0.015 and 0.021 ± 0.003 mM, respectively. The targets of compounds 4 and 5 in the complement activation cascade were also identified. In conclusion, the anti-complementary components of H. angustifolia possessed chemical diversity and consisted mostly of flavonoids and lignans in this study.

Cycloartane triterpenes from Beesia calthaefolia and their anticomplement structure-activity relationship study

Fifteen cycloartane triterpenes were isolated from Beesia calthaefolia and among them one was new cycloartane triterpenoid. The structure of new compound was determined by the application of spectroscopic analyses and chemical methods. The fifteen compounds were evaluated for their anticomplement activity by classic pathway. The structure-activity relationship analysis indicated that the configurations of 12-OH is preferable to be α than β, and 18-OH can decrease while 15-OH can increase the anticomplement activity, but saponin with both 15-OH and 18-OH lost most of its activity. The glycosyl moiety of most isolated cycloartane triterpenes is xylosyl. When xylosyl was substituted by glucosyl or galactosyl, their anticomplement activities were decreased or increased, respectively. Further structure-activity relationship (SAR) studies must be carried out to achieve general conclusions regarding the effect of further functionalizations on the anticomplement saponins.

Bioactivities, isolation and purification methods of polysaccharides from natural products: A review

Polysaccharides play multiple roles and have extensive bioactivities in life process and an immense potential in healthcare, food and cosmetic industries, due to their therapeutic effects and relatively low toxicity. This review describes their major functions involved in antitumor, anti-virus, and anti-inflammatory bioactivities. Due to their enormous structural heterogeneity, the approaches for isolation and purification of polysaccharides are distinct from that of the other macromolecules such as proteins, etc. Yet, to achieve the homogeneity is the initial step for studies of polysaccharide structure, pharmacology, and its structure-activity relationships. According to the experiences accumulated by our lab and the published literatures, this review also introduces the methods widely used in isolation and purification of polysaccharides.

The Structure-Activity Relationship between Marine Algae Polysaccharides and Anti-Complement Activity

In this study, 33 different polysaccharides were prepared to investigate the structure-activity relationships between the polysaccharides, mainly from marine algae, and anti-complement activity in the classical pathway. Factors considered included extraction methods, fractionations, molecular weight, molar ratio of galactose to fucose, sulfate, uronic acid (UA) content, linkage, branching, and the type of monosaccharide. It was shown that the larger the molecular weights, the better the activities. The molar ratio of galactose (Gal) to fucose (Fuc) was a positive factor at a concentration lower than 10 µg/mL, while it had no effect at a concentration more than 10 µg/mL. In addition, sulfate was necessary; however, the sulfate content, the sulfate pattern, linkage and branching had no effect at a concentration of more than 10 µg/mL. Moreover, the type of monosaccharide had no effect. Laminaran and UA fractions had no activity; however, they could reduce the activity by decreasing the effective concentration of the active composition when they were mixed with the active compositions. The effect of the extraction methods could not be determined. Finally, it was observed that sulfated galactofucan showed good anti-complement activity after separation.

One new cycloartane triterpene glycoside from Beesia calthaefolia

One new cycloartane triterpene glycoside (1) was isolated from the whole plant of Beesia calthaefolia. Its structure was elucidated on the basis of extensive spectroscopic data analysis. Its inhibitory effect was measured by the classical pathway of the complement system, and compared with those of known related cycloartane glycosides 2 and 3, previously isolated by us from the same plant. Compounds 1 and 2 exhibited inhibitory activity of complement system with IC50 of 395.3 and 214 μM, respectively. The results suggested that OH at C-12, C-18 and C-15 along with the polarity could affect the inhibitory activity.

Therapeutic Effects of Bupleurum Polysaccharides in Streptozotocin Induced Diabetic Mice

Diabetes mellitus is related to low-grade chronic inflammation and oxidative stress. Bupleurum Polysaccharides (BPs), isolated from Bupleurum smithii var. parvifolium has anti-inflammatory and anti-oxidative properties. However, little is known about its therapeutic effects on diabetes. In this experiment, the effects of BPs on alleviation of diabetes and the underlying mechanisms were investigated. Diabetic mice model was established via successive intraperitoneal injections of streptozotocin (100 mg/kg body weight) for two days. Mice with blood glucose levels higher than 16.8mmol/L were selected for experiments. The diabetic mice were orally administered with BPs (30 and 60 mg/kg) once a day for 35 days. BPs not only significantly decreased levels of blood glucose, but also increased those of serum insulin and liver glycogen in diabetic mice compared to model mice. Additionally, BPs adminstration improved the insulin expression and suppressed the apoptosis in pancreas of the diabetic mice. Histopathological observations further demonstrated that BPs protected the pancreas and liver from oxidative and inflammatory damages. These results suggest that BPs protect pancreatic β cells and liver hepatocytes and ameliorate diabetes, which is associated with its anti-oxidative and anti-inflammatory properties.

Development of a C3c-based ELISA method for the determination of anti-complementary potency of Bupleurum polysaccharides

Traditionally, determination of inhibitory potency of complement inhibitors is performed by the hemolytic assay. However, this assay is not applicable to the lectin pathway, thus impeding the understanding of complement inhibitors against the overall function of the complement system. The main objective of our study was to develop a specific enzyme-linked immunosorbent assay (ELISA) as an alternative method to assess the anti-complement activity, particularly against the lectin pathway. By using respective coating substrates against different activation pathways, followed by capturing the stable C3c fragments, our ELISA method can be used to screen complement inhibitors against the classical pathway and the lectin pathway. The inhibitory effect of suramin on the classical pathway, as measured by our hemolytic assay is consistent with previous reports. Further assessment of suramin and Bupleurum polysaccharides against the lectin pathway showed a good reproducibility of the method. Comparison of the lectin pathway IC₅₀ between Bupleurum smithii var. parvifolium polysaccharides (1.055 mg/mL) and Bupleurum chinense polysaccharides (0.98 mg/mL) showed that, similar to the classical and alterative pathway, these two Bupleurum polysaccharides had comparable anti-complementary properties against the lectin pathway. The results demonstrate that the described ELISA assay can compensate for the shortcomings of the hemolytic assay in lectin pathway.

Structural analysis and anti-complement activity of polysaccharides from Kjellmaniella crsaaifolia

Two polysaccharides, named KCA and KCW, were extracted from Kjellmaniella crassifolia using dilute hydrochloric acid and water, respectively. Composition analysis showed that these polysaccharides predominantly consisted of fucose, with galactose, mannose and glucuronic acid as minor components. After degradation and partial desulfation, electrospray ionization mass spectrometry (ESI-MS) was performed, which showed that the polysaccharides consisted of sulfated fucooligosaccharides, sulfated galactofucooligosaccharides and methyl glycosides of mono-sulfated/multi-sulfated fucooligosaccharides. The structures of the oligomeric fragments were further characterized by electrospray ionization collision-induced dissociation tandem mass spectrometry (ESI-CID-MS2 and ESI-CID-MS3). Moreover, the activity of KCA and KCW against the hemolytic activity of both the classical and alternative complement pathways was determined. The activity of KCA was found to be similar to KCW, suggesting that the method of extraction did not influence the activity. In addition, the degraded polysaccharides (DKCA and DKCW) displayed lower activity levels than the crude polysaccharides (KCA and KCW), indicating that molecular weight had an effect on activity. Moreover, the desulfated fractions (ds-DKCA and ds-DKCW) showed less or no activity, which confirmed that sulfate was important for activity. In conclusion, polysaccharides from K. crassifolia may be good candidates for the treatment of diseases involving the complement pathway.

A new saikogenin from the roots of Bupleurum bicaule

AIM

To study the chemical constituents from the roots of Buleurum bicaule Helm (Apiaceae).

METHOD

Silica gel, Sephadex LH-20, MPLC Rp-C18 column chromatography, and HPLC were used for isolation of compounds. The structures were elucidated on the basis of 1D- and 2D-NMR technology and HRESI-MS. Compounds were evaluated in vitro for their inhibitory ability against the proliferation of rat mesangial cells by the MTT method.

RESULTS

Twelve compounds were isolated, and their structures were identified on the basis of their spectroscopic and physico-chemical properties as 13, 28-epoxy-olean-11-en-3-one (1), saikogenin E (2), saikogenin G (3), 11α-methoxy-3β, 16β, 23, 28-tetrahydroxyolean-12-ene (4), saikogenin D (5), prosaikogenin F (6), prosaikogenin A (7), prosaikogenin G (8), prosaikogenin D (9), laccaic acid (10b), methyl gallate (11), and ethyl gallate (12). Compounds 1, 2, 7, 8, and 10 were observed to have inhibitory activity against mesangial cell proliferationin to different degrees.

CONCLUSION

Compound 1, 8, and 10 exhibit significant inhibitory effects on rat mesangial cell proliferation induced by Ang II.

Intestinal bacterial metabolism and anti-complement activities of three major components of the seeds of Entada phaseoloides

The present study aimed to investigate the metabolism of Entadae Semen by human fecal bacteria to clarify the relationship between its pharmacological activities and intestinal metabolism. Three major components (phaseoloidin, entadamide A-β-D-glucopyranoside and entadamide A) were isolated and identified from Entadae Semen and then incubated with human fecal microflora in vitro to investigate the metabolic processes. The metabolites were analyzed with high-performance liquid chromatography (HPLC). The anti-complement activities of the three components and their metabolites produced by human fecal microflora were evaluated in vitro using a hemolysis assay. Phaseoloidin and entadamide A-β-D-glucopyranoside were metabolized into their respective aglycones during the incubation process, which enhanced their anti-complement effects. These results indicated that the presence of intestinal bacteria likely plays an important role and that the pharmacological effects of Entadae Semen may be dependent on intestinal bacterial metabolism.

Simulated gastrointestinal tract metabolism and pharmacological activities of water extract of Scutellaria baicalensis roots

ETHNOPHARMACOLOGICAL RELEVANCE SCUTELLARIA BAICALENSIS: Georgi (Labiatae) is a well-known traditional Chinese medicine to treat inflammation, cardiovascular diseases, respiratory and gastrointestinal infections, etc. The present study was to understand the metabolism of the root of Scutellaria baicalensis (a.k.a. Huangqin in Chinese) in the gastrointestinal tract and the correlation between the metabolites and their respective pharmacological activities.

MATERIALS AND METHODS

The water extract of the root of Scutellaria baicalensis (WESB) was incubated with simulated gastric and intestinal juices, and human fecal microflora for 24h at 37 °C. The HPLC-DAD analysis was used to monitor the in vitro metabolic process and identify its metabolites by comparing their absorption spectrum and retention time with those of chemical references. The in vitro anticomplementary and antimicrobial activity was evaluated with hemolysis assay, agar disc-diffusion method and MIC value, respectively.

RESULTS

Main constituents of WESB remain unchanged during the incubation with simulated gastric juice (pH = 1.5) and intestinal juice (pH = 6.8), whereas four flavones, baicalin, wogonoside, oroxyloside and norwogonoside were metabolized into their respective aglycons by human intestinal bacteria. All four metabolites were demonstrated to have higher anticomplementary and antimicrobial activity than those of WESB. The anticomplementary active metabolites were identified to be baicalein, oroxylin A and norwogonin, among them, norwogonin is the most active compound.

CONCLUSION

The presence of intestinal bacteria is demonstrated to play an important role in the gastrointestinal metabolism of WESB, and the pharmacological effects of Scutellaria baicalensis may be dependent on the intestinal bacteria metabolism.

Anticomplement monoterpenoid glucosides from the root bark of Paeonia suffruticosa

Six new (1-6) and 19 known monoterpenoid glucosides were isolated from the root bark of Paeonia suffruticosa. The monoterpenoid glucosides 1, 2, 7, 10-19, and 22 exhibited anticomplement effects with CH50 and AP50 values ranging from 0.14 to 2.67 mM and 0.25 to 3.67 mM, respectively. In a mechanistic study, suffrupaeoniflorin A (1) interacted with C1q, C3, C5, and C9, while galloylpaeoniflorin (12) and galloyloxypaeoniflorin (19) acted on C1q, C3, and C5 components in the complement activation cascade.

Isolation of an anti-complementary polysaccharide from the root of Bupleurum chinense and identification of its targets in complement activation cascade

AIM

To isolate and characterize the anti-complementary polysaccharide from the root of Bupleurum chinense.

METHODS

Bioactivity-guided fractionation and purification was used to obtain the anti-complementary polysaccharide from the hot-water extract of the root of Bupleurum chinense. The polysaccharide was characterized by various chemical and spectral analyses. The anti-complementary activities were evaluated by hemolytic assay in vitro. The action targets were identified in the system with individual complement-depleted sera.

RESULTS

A homogeneous polysaccharide BC-PS2 was isolated as an anti-complementary agent. It was identified as a branched polysaccharide with an average molecular weight about 2 000 KDa, composed of Glc, Ara, Gal, and Man in the ratio 3.5 : 2.4 : 2.0 : 1.0, respectively, along with a trace of Rha and Xyl, and only 1.11% of protein. The main linkages of the residues of BC-PS2 include terminal, 1, 6-linked, 1, 3-linked and 1, 3, 6-linked Glcp, terminal and 1, 5-linked Araf, terminal, 1, 4-linked, 1, 6-linked and 1, 4, 6-linked Galp, terminal, and, 1, 4-linked and 1, 4, 6-linked Manp. The bioassay experiments revealed that BC-PS2 inhibited complement activation on both the classical and alternative pathways, with CH50 and AP50 of (0.222 ± 0.013) and (0.356 ± 0.032) mg·mL(-1), respectively. Preliminary mechanism studies indicated that BC-PS2 interacted with C1q, C2, and C9 components.

CONCLUSION

The results demonstrated that BC-PS2 is an anti-complementary polysaccharide, and should be important constituent of the root of Bupleurum chinense for its application in the treatment of diseases associated with the excessive activation of complement system.

Two New Compounds and Anti-complementary Constituents from Amomum tsao-ko

Two new compounds, (2 R,3 R,4 R)–3′,5′-dimethoxy-3,4,7,4′-tetrahydroxy-flavan (1) and 2-(4-hydroxy-3-methoxybenzoyl)-4-methoxy-benzaldehyde (2), together with 35 known phenolic compounds were obtained from the fruits of Amomum tsao-ko. Structures of the new compounds were elucidated on the basis of spectroscopic means, including 2D NMR, and high-resolution MS analysis. The isolated compounds were tested in vitro for their complement-inhibitory properties against the classical pathway (CP) and alternative pathway (AP). The results showed that 14 compounds exhibited anti-complementary activities against the CP and AP with CH50 values of 0.42 - 4.43 mM and AP50 values of 0.53 −1.51 mM. Preliminary mechanism studies showed that 1,7-bis(4-hydroxyphenyl)–4( E)-hepten-3-one (8) blocked C1q, C2, C3, C4, C5 and C9 components of the complement system, and hydroquinone (15) acted on C1q, C2, C3, C5 and C9 components.

Traditional Use, Pharmacology, Toxicology, and Quality Control of Species in Genus Bupleurum L

Many species of genus Bupleurum L. have been pharmaceutically used mainly in Asia and Europe for thousand years. Their roots are the most popular ingredients in Chinese materia medica prescriptions for the treatment of inflammatory diseases and auto-immune diseases. A plenty of chemical constituents have been isolated and identified from the species in Bupleurum L., such as saikosaponins, polysaccharides, volatile oils, flavonoids, polyacetylenes, lignins, and coumarins, most of which possess a variety of biological activities, especially for the hepatoprotective effect, antitumor activity, immunoregulation, and febrifuge efficacy. Therefore, the species in genus Bupleurum L. could be potential herbs of immunomodulator, antineoplastic, anti-oxidant, etc. Meanwhile, as potential toxicities have been discovered in some constituents, it is urgent to establish a comprehensive quality evaluation system to ensure the safety and efficiency of herbs. This paper reviews on the phytochemical and pharmacological studies, especially for the toxicology and quality control of the species in Bupleurum L., which is a reference for the species in this genus for safe usage and further development.