Antitussive effect of a fixed combination of Justicia adhatoda, Echinacea purpurea and Eleutherococcus senticosus extracts in patients with acute upper respiratory tract infection: A comparative, randomized, double-blind, placebo-controlled study

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.

Overview of the Justicia Genus: Insights into Its Chemical Diversity and Biological Potential

The genus Justicia has more than 600 species distributed in both hemispheres, in the tropics and temperate regions, and it is used in the treatment of numerous pathologies. This study presents a review of the biological activities of plant extracts and isolated chemical constituents of Justicia (ACANTHACEAE), identified in the period from May 2011 to August 2022. We analyzed over 176 articles with various biological activities and chemical compound descriptions present in the 29 species of Justicia. These have a variety of applications, such as antioxidant and antimicrobial, with alkaloids and flavonoids (e.g., naringenin) the most frequently identified secondary metabolites. The most observed species were Justicia gendarussa Burm., Justicia procumbens L., Justicia adhatoda L., Justicia spicigera Schltdl, and Justicia pectoralis Jacq. The frontier molecular orbitals carried out using density functional theory (M062X and basis set 6-311++G(d,p) indicate reactive sites for naringenin compound and a chemical reaction on phytomedicine activity. The energy gap (206.99 kcal/mol) and dimer solid state packing point to chemical stability. Due to the wide variety of pharmacological uses of these species, this review points toward the development of new phytomedicines.

Phytonutrient Inhibitors of SARS-CoV-2/NSP5-Encoded Main Protease (Mpro) Autocleavage Enzyme Critical for COVID-19 Pathogenesis

The genomic reshuffling, mutagenicity, and high transmission rate of the SARS-CoV-2 pathogen highlights an urgent need for effective antiviral interventions for COVID-19 control. Targeting the highly conserved viral genes and/or gene-encoded viral proteins such as main proteinase (M^pro), RNA-dependent RNA polymerase (RdRp) and helicases are plausible antiviral approaches to prevent replication and propagation of the SARS-CoV-2 infection. Coronaviruses (CoVs) are prone to extensive mutagenesis; however, any genetic alteration to its highly conserved M^pro enzyme is often detrimental to the viral pathogen. Therefore, inhibitors that target the M^pro enzyme could reduce the risk of mutation-mediated drug resistance and provide effective antiviral protection. Several existing antiviral drugs and dietary bioactives are currently repurposed to treat COVID-19. Dietary bioactives from three ayurvedic medicinal herbs, 18 β-glycyrrhetinic acid (ΔG = 8.86 kcal/mol), Solanocapsine (ΔG = 8.59 kcal/mol), and Vasicoline (ΔG = 7.34 kcal/mol), showed high-affinity binding to M^pro enzyme than the native N3 inhibitor (ΔG = 5.41 kcal/mol). Flavonoids strongly inhibited SARS-CoV-2 M^pro with comparable or higher potency than the antiviral drug, remdesivir. Several tannin hydrolysates avidly bound to the receptor-binding domain and catalytic dyad (His₄₁ and Cys₁₄₅) of SARS-CoV-2 M^pro through H-bonding forces. Quercetin binding to M^pro altered the thermostability of the viral protein through redox-based mechanism and inhibited the viral enzymatic activity. Interaction of quercetin-derivatives with the M^pro seem to be influenced by the 7-OH group and the acetoxylation of sugar moiety on the ligand molecule. Based on pharmacokinetic and ADMET profiles, several phytonutrients could serve as a promising redox nutraceutical for COVID-19 management.

Adverse Effects of Andrographolide Derivative Medications Compared to the Safe use of Herbal Preparations of Andrographis paniculata: Results of a Systematic Review and Meta-Analysis of Clinical Studies

Background and objective:Andrographis paniculata (AP) is a traditionally used herbaceous plant, whose main active constituent is andrographolide. Andrographolide derivative medications and herbal preparations of AP are often used to treat respiratory tract infections. This study aims to systematically evaluate the safety of andrographolide derivative medications and herbal preparations of AP based on clinical studies.

Methods: English and Chinese databases were searched for all types of clinical studies that reported adverse drug reactions (ADRs) and adverse events (AEs) of andrographolide derivative medications and herbal preparations of AP. The ADRs and AEs were classified according to manifestations, and graded according to severity. Single-rate meta-analysis was performed for ADR incidence using R software.

Results: A total of 262 studies were included, including 125 randomized controlled trials, 23 non-randomized controlled trials, 6 case series, and 108 case reports. In 9490 participants using andrographolide derivative injections, 383 (4.04%) reported ADRs. Meta-analysis showed that the ADR incidence of three most frequently used injections of andrographolide derivatives (andrographolide sulfonate, potassium sodium dehydroandrographolide succinate, and potassium dehydroandrographolide succinate) were 5.48% [95% CI (4.47%, 6.72%)], 3.69% [95% CI (2.59%, 4.94%)] and 5.33% [95% CI (3.68%, 7.72%)], respectively, which may be slightly higher than the actual ADR incidence, because only studies that reported the occurrence of ADRs or AEs were included, but studies without ADR and AE were not included. The ADRs of andrographolide derivative injections were mainly gastrointestinal, skin and subcutaneous tissue disorders, and anaphylaxis. Fifty-five patients experienced life-threatening anaphylactic shock, three patients died, and the causation attributed to the andrographolide derivative injection. Other ADRs were mild, moderate or medically significant. Nine herbal preparations of AP were tested in 10 studies, and the reported ADRs were mainly mild to moderate gastrointestinal, skin and subcutaneous tissue disorders. Except for five patients using andrographolide derivative injections eventually died, most of the ADRs were alleviated after drug withdrawal and symptomatic treatment.

Conclusions: The ADRs of andrographolide derivative medications are few, but can be life-threatening, mainly gastrointestinal, skin and subcutaneous tissue disorders, and anaphylaxis. Injections of andrographolide derivatives should be used with caution. Herbal preparations of AP are essentially safe.

Systematic Review Registration: [website], identifier [registration number]

Non-pharmacological remedies for post-viral acute cough

The post-viral acute cough (PAC) is a widespread symptom, mainly in childhood and adolescence, and is usually associated with an acute upper respiratory infection, namely the common cold. The use of cough relievers is, therefore, impressive, as documented by the market data. There are many medical devices and dietary supplements for treating PAC, which contain non-pharmacological components. Ancient people used traditional herbs to treat PAC. Thus, a well-established tradition considers natural remedies as an effective and safe way to relieve PAC. The herbal agents include polyphenols, flavonoids, saponins, glucosides, and alkaloids. Also, the European Medicine Agency has recognized the value of plant extracts and other natural substances to treat PAC. Nevertheless, a few studies investigated the role of non-pharmacologic remedies for PAC. There is some evidence for honey, glycerol, Althea officinalis, Drosera rotundifolia, Grindelia, Hedera helix, Pelargonium sidoides, Sambucus nigra, Thymus vulgaris, hyaluronic acid, and saline solutions. However, further rigorous studies should confirm natural products' efficacy and safety to relieve PAC.

Andrographis paniculata (Burm. f.) Wall. ex Nees: An Updated Review of Phytochemistry, Antimicrobial Pharmacology, and Clinical Safety and Efficacy

Infectious disease (ID) is one of the top-most serious threats to human health globally, further aggravated by antimicrobial resistance and lack of novel immunization options. Andrographis paniculata (Burm. f.) Wall. ex Nees and its metabolites have been long used to treat IDs. Andrographolide, derived from A. paniculata, can inhibit invasive microbes virulence factors and regulate the host immunity. Controlled clinical trials revealed that A. paniculata treatment is safe and efficacious for acute respiratory tract infections like common cold and sinusitis. Hence, A. paniculata, mainly andrographolide, could be considered as an excellent candidate for antimicrobial drug development. Considering the importance, medicinal values, and significant role as antimicrobial agents, this study critically evaluated the antimicrobial therapeutic potency of A. paniculata and its metabolites, focusing on the mechanism of action in inhibiting invasive microbes and biofilm formation. A critical evaluation of the secondary metabolites with the aim of identifying pure compounds that possess antimicrobial functions has further added significant values to this study. Notwithstanding that A. paniculata is a promising source of antimicrobial agents and safe treatment for IDs, further empirical research is warranted.

The effectiveness of a traditional Persian medicine preparation in the treatment of chronic cough: A randomized, double-blinded, placebo-controlled clinical trial

OBJECTIVES

The roots and rhizomes of licorice (Glycyrrhiza glabra L.) are used in traditional Persian medicine for the treatment of numerous diseases. A chronic cough is a non-specific reaction to irritation anywhere in the respiratory system. It usually lasts for more than eight weeks. The current study aimed to evaluate the effect of a modified traditional Persian medicine preparation, licorice pastille, in healing a chronic cough.

METHODS

Through a randomized, double-blinded, placebo-controlled clinical trial was performed in a respiratory disease clinic in Shiraz, Iran; between October 2016 and December 2017. Seventy participants with a chronic cough took part in the trial. The outcome measures were as the daily cough scores (the score being logged via patient symptoms, diary, and the visual analogue scale) and the quality of life measure of chronic cough according to the Leicester Cough Questionnaire.

RESULTS

At baseline, there were no significant differences in the demographic or clinical (cough score) characteristics between the two groups. There was complete adherence to protocol in both groups but, the drop-out rate was 4 patients in the placebo and 6 ones in the intervention groups. The results at the end of the trial (Week 2) and follow-up (Week 4) demonstrated the efficacy of the licorice pastille in terms of the cough severity score against the placebo group. This item showed a significant decrease in the intervention group (1.2 ± 0.93) comparing to the placebo one (1.8 ± 1.03) at follow-up time. No major side effects were reported during the study and follow-up time.

CONCLUSIONS

Licorice pastille could be a promising choice in the treatment of a chronic cough of unknown origin.

Self-Care for Common Colds: The Pivotal Role of Vitamin D, Vitamin C, Zinc, and Echinacea in Three Main Immune Interactive Clusters (Physical Barriers, Innate and Adaptive Immunity) Involved during an Episode of Common Colds-Practical Advice on Dosages and on the Time to Take These Nutrients/Botanicals in order to Prevent or Treat Common Colds

Maintaining a normal healthy immune defense system lowers the incidence and/or the severity of symptoms and/or the duration of common cold (CC). Physical barriers and innate and adaptive immunity have been involved during a CC episode. Vitamins C and D, zinc, and Echinacea have evidence-based efficacy on these immune system barriers. This review includes 82 eligible studies to consider the preventive role of these nutrients in immune clusters and in CC to provide advice on dosage and assumption of these nutrients. Regarding vitamin C, regular supplementation (1 to 2 g/day) has shown that vitamin C reduces the duration (in adults by 8%, in children by 14%) and the severity of CC. Considering zinc, the supplementation may shorten the duration of colds by approximately 33%. CC patients may be instructed to try zinc within 24 hours of onset of symptoms. As for vitamin D, the supplementation protected against CC overall, considering baseline levels and age. Patients with vitamin D deficiency and those not receiving bolus doses experienced the most benefit. Regarding Echinacea, prophylactic treatment with this extract (2400 mg/day) over 4 months appeared to be beneficial for preventing/treating CC. In conclusion, the current evidence of efficacy for zinc, vitamins D and C, and Echinacea is so interesting that CC patients may be encouraged to try them for preventing/treating their colds, although further studies are needed on this topic.

A reappraisal of the mucoactive activity and clinical efficacy of bromhexine

Since its introduction to the market in 1963, bromhexine, an over-the-counter drug, has been investigated for its activity in animal models and in humans with diverse respiratory conditions. Bromhexine is a derivate of the Adhatoda vasica plant used in some countries for the treatment of various respiratory diseases. Bromhexine has been found to enhance the secretion of various mucus components by modifying the physicochemical characteristics of mucus. These changes, in turn, increase mucociliary clearance and reduce cough. Principal clinical research studies were primarily developed in an era when stringent methodological approaches and good clinical practices were not developed yet. Clinical studies were conducted mainly in patients with chronic bronchitis and in patients with various respiratory diseases, and demonstrated the efficacy of bromhexine in improving respiratory symptoms. Furthermore, the co-administration of antibiotics with bromhexine amplified the actions of the antibiotic. Although the clinical evidence shows only modest but positive results, bromhexine is indicated for its mucoactive activity. Larger trials with adequate methodology are required to identify when treatment with bromhexine can improve clinical outcomes.