Some new insights into the biological activities of carboxymethylated polysaccharides from Lasiodiplodia theobromae

BACKGROUND

Carboxymethylated Lasiodiplodan (LaEPS-C), Lasiodiplodia theobromae β-glucan exopolysaccharide derivative, has a well-known range of biological activities. Compared to LaEPS-C, its fractions, Linear (LLaEPS-C) and Branched (BLaEPS-C), have biological potentialities scarcely described in the literature. So, in this study, we investigate the immunomodulatory, antiviral, antiproliferative, and anticoagulant activities of LLaEPS-C and BLaEPS-C and compare them to the LaEPS-C.

METHODS

LaEPS was obtained from L. theobromae MMBJ. After carboxymethylation, LaEPS-C structural characteristics were confirmed by Elementary Composition Analysis by Energy Dispersive X-Ray Detector (EDS), Fourier Transform Infrared (FTIR), and Nuclear Magnetic Resonance (NMR). The immunomodulatory activity on cytokine secretion was evaluated in human monocyte-derived macrophage cultures. The antiviral activity was evaluated by Hep-2 cell viability in the presence or absence of hRSV (human respiratory syncytial virus). In vitro antiproliferative activity was tested by sulforhodamine B assay. The anticoagulant activity was determined by APTT (Activated Partial Thromboplastin Time) and PT (Prothrombin Time).

RESULTS

LaEPS-C showed low macrophage cell viability only at 100 µg/mL (52.84 ± 24.06, 48 h), and LLaEPS-C presented no effect. Conversely, BLaEPS-C showed cytotoxicity from 25 to 100 µg/mL (44.36 ± 20.16, 40.64 ± 25.55, 33.87 ± 25.16; 48 h). LaEPS-C and LLaEPS-C showed anti-inflammatory activity. LaEPS-C presented this at 100 µg/mL (36.75 ± 5.53, 48 h) for IL-10, and LLaEPS-C reduces TNF-α cytokine productions at 100 µg/mL (18.27 ± 5.80, 48 h). LLaEPS-C showed an anti-hRSV activity (0.7 µg/ml) plus a low cytotoxic activity for Hep-2 cells (1.4 µg/ml). LaEPS-C presented an antiproliferative activity for NCI-ADR/RES (GI50 65.3 µg/mL). A better PT was achieved for LLaEPS-C at 5.0 µg/mL (11.85 ± 0.87s).

CONCLUSIONS

These findings demonstrated that carboxymethylation effectively improves the biological potential of the LaEPS-C and their fractions. From those polysaccharides tested, LLaEPS provided the best results with low toxicity for anti-inflammatory, antiviral, and anticoagulant activities.

Natural Products for the Prevention and Treatment of Common Cold and Viral Respiratory Infections

The common cold is generally considered a usually harmless infectious disease of the upper respiratory pathway, with mostly mild symptoms. However, it should not be overlooked, as a severe cold can lead to serious complications, resulting in hospitalization or death in vulnerable patients. The treatment of the common cold remains purely symptomatic. Analgesics as well as oral antihistamines or decongestants may be advised to relieve fever, and local treatments can clear the airways and relieve nasal congestion, rhinorrhea, or sneezing. Certain medicinal plant specialties can be used as therapy or as complementary self-treatment. Recent scientific advances discussed in more detail in this review have demonstrated the plant's efficiency in the treatment of the common cold. This review presents an overview of plants used worldwide in the treatment of cold diseases.

Kakkonto Inhibits Cytokine Production Induced by Rhinovirus Infection in Primary Cultures of Human Nasal Epithelial Cells

Rhinovirus (RV) is a primary etiologic agent of common cold that can subsequently acutely exacerbate bronchial asthma or chronic obstructive pulmonary disease. Kakkonto (Ge-gen-tang in Chinese), one of the most frequently prescribed traditional Japanese (Kampo) medicines, is used for treating common cold, shoulder stiffness, or inflammatory diseases of the upper body. Previous experimental studies have indicated that kakkonto exerts antiviral and anti-inflammatory effects on the influenza virus and the human respiratory syncytial virus. However, there is a lack of reports investigating the efficacy of kakkonto in RV infection. Hence, the aim of the current study was to investigate the effects of kakkonto on RV infection of human nasal epithelial (HNE) cells. HNE cells obtained via endoscopic sinus surgery were cultured and infected with RV14, with or without kakkonto treatment. The supernatants from the cells were collected, and the RV14 titer and cytokine levels were assessed. Reverse transcription-polymerase chain reaction was performed to determine the amount of viral RNA, while the level of nuclear factor kappa B (NF-κB) subunits in the nucleus was assessed by enzyme-linked immunosorbent assay. Although kakkonto treatment did not reduce RV14 titer or RNA levels, indicating that it did not inhibit RV14 proliferation, it was found to reduce the production of specific pro-inflammatory cytokines, including interleukin (IL)-8, tumor necrosis factor (TNF)-α, and monocyte chemotactic protein-1 (MCP-1). Unlike that observed with the kakkonto extract, none of the crude drugs contained in kakkonto reduced IL-8 level. Furthermore, though kakkonto treatment significantly reduced p50 levels, it did not impact the p65 subunit of NF-κB. These results indicated that kakkonto can inhibit inflammation caused by RV infection and may exert an immunomodulatory effect on HNE cells. This is the first report to elucidate the effects of kakkonto extract on RV infection in primary cultures of HNE cells, providing evidence that kakkonto may act as an effective therapy for RV infection and subsequent airway inflammation.

Analysis of Traditional Chinese Medicine Diagnosis and Treatment Strategies for COVID-19 Based on "The Diagnosis and Treatment Program for Coronavirus Disease-2019" from Chinese Authority

In December 2019, coronavirus disease-2019 (COVID-19) broke out in Wuhan and other places. Seven versions of the Diagnosis and Treatment Program for Coronavirus Disease-2019 successively issued by the Chinese government have designated traditional Chinese medicine (TCM) as a necessary medical strategy. Based on the changes in TCM diagnosis and treatment strategies in these seven versions of Diagnosis and Treatment Program for Coronavirus Disease-2019, this paper collected data reported by the Chinese government media; analyzed the understanding of the etiology, pathogenesis, syndrome differentiation, treatment methods, and prescriptions of COVID-19 by TCM and evaluated the clinical efficacy of TCM strategies. COVID-19 is associated with TCM disease of pestilence, and its pathogenesis can be summarized as an "epidemic pathogen invading the body, followed by entering the internal organs and transforming into heat, resulting in pathogen trapping in the interior and healthy qi collapsing, and deficiency of qi and yin". Pathological processes should be emphasized in syndrome differentiation. The manifestations of qi deficiency and yin deficiency are exhibited during the recovery period. TCM strategies represented by Qing Fei Pai Du Tang have shown apparent advantages in improving symptoms, promoting virus clearance, and shortening hospitalization, as well as surprising efficacy of zero patient progressing from mild to severe cases in a TCM cabin hospital. Clinical data illustrate the effectiveness of TCM strategies proposed by the Chinese government. This major epidemic may bring new opportunities for TCM development.

In vitro antiviral, anti-inflammatory, and antioxidant activities of the ethanol extract of Mentha piperita L

The objective of this study is to investigate the antiviral, anti-inflammatory, and antioxidant effects of the ethanol extract of Mentha piperita L. leaves (MPE). M. piperita L. leaves were extracted by reflux with ethanol. Total phenolic acid and total flavonoid content were determined. The antiviral activity of MPE against the respiratory syncytial virus (RSV) and the anti-inflammatory activity were evaluated in vitro. The levels of key pre-inflammatory mediators and cytokines including nitric oxide (NO), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and prostaglandin E2 (PGE2) were determined. The antioxidant activities were also evaluated using a colorimetry method. MPE contained high levels of phenolic acid and flavonoid, showed antiviral activity against RSV with a high selectivity index, and significantly decreased the production of NO, TNF-α, IL-6, and PGE2 in lipopolysaccharide-stimulated RAW 264.7 cells. Meanwhile, MPE showed potential free-radical scavenging activities. These results indicate that Mentha piperita L. might be a good source of medicinal plants.

Inhibition of Murine Norovirus and Feline Calicivirus by Edible Herbal Extracts

Human noroviruses (HuNoVs) cause foodborne and waterborne viral gastroenteritis worldwide. Because HuNoV culture systems have not been developed thus far, no available medicines or vaccines preventing infection with HuNoVs exist. Some herbal extracts were considered as phytomedicines because of their bioactive components. In this study, the inhibitory effects of 29 edible herbal extracts against the norovirus surrogates murine norovirus (MNV) and feline calicivirus (FCV) were examined. FCV was significantly inhibited to 86.89 ± 2.01 and 48.71 ± 7.38% by 100 μg/mL of Camellia sinensis and Ficus carica, respectively. Similarly, ribavirin at a concentration of 100 μM significantly reduced the titer of FCV by 77.69 ± 10.40%. Pleuropterus multiflorus (20 μg/mL) showed antiviral activity of 53.33 ± 5.77, and 50.00 ± 16.67% inhibition was observed after treatment with 20 μg/mL of Alnus japonica. MNV was inhibited with ribavirin by 59.22 ± 16.28% at a concentration of 100 μM. Interestingly, MNV was significantly inhibited with 150 µg/mL Inonotus obliquus and 50 μg/mL Crataegus pinnatifida by 91.67 ± 5.05 and 57.66 ± 3.36%, respectively. Treatment with 20 µg/mL Coriandrum sativum slightly reduced MNV by 45.24 ± 4.12%. The seven herbal extracts of C. sinensis, F. carica, P. multiflorus, A. japonica, I. obliquus, C. pinnatifida, and C. sativum may have the potential to control noroviruses without cytotoxicity.

Consistent Efficacy of Wendan Decoction for the Treatment of Digestive Reflux Disorders

Gastroesophageal reflux disease (GERD) and bile reflux gastritis (BRG) are common gastrointestinal (GI) disorders with unmet medical needs. Traditional Chinese medicine has long been used for the treatment of GERD and BRG whereas the ginger-containing formula Wendan decoction (WDD) targets homeostatic disturbances characterized by "reflux" and "gut-juice exposure" problems. Here we used WDD as a therapeutic tool to unravel the common pathogenesis of GI reflux disorders. Control clinical trials reporting the WDD-treated patients with GERD and BRG were included in this systematic review and meta-analysis. Outcome measurements were clinical efficacy defined by symptom relief with normal GI endoscopy, radiology, and pathology. Eventually, 33 studies involved 3253 participants (1351 vs. 1035 of the BRG in 20 publications, 449 vs. 418 of the GERD in 13 studies, and 194 vs. 159 of relapse rate in 6 trials). Pooled data showed a consistent therapeutic efficacy of WDD on BRG (OR = 6.00, 95%C = 4.68-7.69) and GERD (OR = 4.39, 95%CI = 2.72-7.07). The relapse rate was 12.4% for WDD, significantly lower than 44.0% for conventional therapies (OR = 0.14, 95%CI = 0.08-0.26). The consistent therapeutic efficacy of the single TCM formula on GERD and BRD indirectly indicates reflux as a common pathogenesis in reflux-associated GI disorders.

Characterization of the anti-influenza activity of the Chinese herbal plant Paeonia lactiflora

Bai Shao (BS, the root of Paeonia lactiflora Pall.), a common Chinese herb in many recipes used to treat viral infection and liver diseases, is recognized for its ability to nourish menstruation, its Yin convergence, and as an antiperspirant. However, the mechanism and components for its antiviral function remain to be elucidated. In this study, an ethanolic extract of BS was further partitioned into aqueous and organic parts (EAex) for in vitro functional study and in vivo efficacy testing. EAex exhibited an IC50 of 0.016 ± 0.005 mg/mL against influenza virus A/WSN/33 (H1N1), with broad-spectrum inhibitory activity against different strains of human influenza A viruses, including clinical oseltamivir-resistant isolates and an H1N1pdm strain. The synthesis of both viral RNA and protein was profoundly inhibited when the cells were treated with EAex. A time-of-addition assay demonstrated that EAex exerted its antiviral activity at various stages of the virus replication cycle. We addressed its antiviral activity at virus entry and demonstrated that EAex inhibits viral hemagglutination and viral binding to and penetration into host cells. In vivo animal testing showed that 200 mg/kg/d of EAex offered significant protection against viral infection. We conclude that BS possesses antiviral activity and has the potential for development as an anti-influenza agent.

Water extract of Pueraria lobata Ohwi has anti-viral activity against human respiratory syncytial virus in human respiratory tract cell lines

Human respiratory syncytial virus (HRSV) infects all age groups and causes bronchiolitis, pneumonia, and acute respiratory distress syndrome with a significant mortality rate. To date, only ribavirin has been used to manage HRSV infection. However, ribavirin is expensive with an only modest effect. Furthermore, ribavirin has several side effects, which means it has limited clinical benefit. Pueraria lobata Ohwi (P. lobata) is a common ingredient of Ge-Gen-Tang (Kakkon-to) and Sheng-Ma-Ge-Gen-Tang (Shoma-kakkon-to), which are prescriptions of Chinese traditional medicine proven to have antiviral activity against HRSV. Therefore, it was hypothesized that P. lobata might be effective against HRSV. To find a cost-effective therapeutic modality, both human upper (HEp-2) and lower (A549) respiratory tract cell lines were used to test the hypothesis that P. lobata could inhibit HRSV-induced plaque formation. Results showed that the water extract of P. lobata was effective (p < 0.0001) against HRSV-induced plaque formation. P. lobata was more effective when given prior to viral inoculation (p < 0.0001) by inhibiting viral attachment (p < 0.0001) and penetration (p < 0.0001). However, supplementation with P. lobata could not stimulate interferon secretion after HRSV infection. In conclusion, P. lobata has antiviral activity against HRSV-induced plaque formation in airway mucosa mainly by inhibiting viral attachment and internalization. Further identification of effective constituents could contribute to the prevention of HRSV infection.