Identification and Characterization of Baicalin as a Phosphodiesterase 4 Inhibitor

The protective effects of baicalin for respiratory diseases: an update and future perspectives

Background: Respiratory diseases are common and frequent diseases. Due to the high pathogenicity and side effects of respiratory diseases, the discovery of new strategies for drug treatment is a hot area of research. Scutellaria baicalensis Georgi (SBG) has been used as a medicinal herb in China for over 2000 years. Baicalin (BA) is a flavonoid active ingredient extracted from SBG that BA has been found to exert various pharmacological effects against respiratory diseases. However, there is no comprehensive review of the mechanism of the effects of BA in treating respiratory diseases. This review aims to summarize the current pharmacokinetics of BA, baicalin-loaded nano-delivery system, and its molecular mechanisms and therapeutical effects for treating respiratory diseases.

Method: This review reviewed databases such as PubMed, NCBI, and Web of Science from their inception to 13 December 2022, in which literature was related to “baicalin”, “Scutellaria baicalensis Georgi”, “COVID-19”, “acute lung injury”, “pulmonary arterial hypertension”, “asthma”, “chronic obstructive pulmonary disease”, “pulmonary fibrosis”, “lung cancer”, “pharmacokinetics”, “liposomes”, “nano-emulsions”, “micelles”, “phospholipid complexes”, “solid dispersions”, “inclusion complexes”, and other terms.

Result: The pharmacokinetics of BA involves mainly gastrointestinal hydrolysis, the enteroglycoside cycle, multiple metabolic pathways, and excretion in bile and urine. Due to the poor bioavailability and solubility of BA, liposomes, nano-emulsions, micelles, phospholipid complexes, solid dispersions, and inclusion complexes of BA have been developed to improve its bioavailability, lung targeting, and solubility. BA exerts potent effects mainly by mediating upstream oxidative stress, inflammation, apoptosis, and immune response pathways. It regulates are the NF-κB, PI3K/AKT, TGF-β/Smad, Nrf2/HO-1, and ERK/GSK3β pathways.

Conclusion: This review presents comprehensive information on BA about pharmacokinetics, baicalin-loaded nano-delivery system, and its therapeutic effects and potential pharmacological mechanisms in respiratory diseases. The available studies suggest that BA has excellent possible treatment of respiratory diseases and is worthy of further investigation and development.

Pharmacological effects of baicalin in lung diseases

The flavonoids baicalin and baicalein were discovered in the root of Scutellaria baicalensis Georgi and are primarily used in traditional Chinese medicine, herbal supplements and healthcare. Recently, accumulated investigations have demonstrated the therapeutic benefits of baicalin in treating various lung diseases due to its antioxidant, anti-inflammatory, immunomodulatory, antiapoptotic, anticancer, and antiviral effects. In this review, the PubMed database and ClinicalTrials website were searched with the search string "baicalin" and "lung" for articles published between September 1970 and March 2023. We summarized the therapeutic role that baicalin plays in a variety of lung diseases, such as chronic obstructive pulmonary disease, asthma, pulmonary fibrosis, pulmonary hypertension, pulmonary infections, acute lung injury/acute respiratory distress syndrome, and lung cancer. We also discussed the underlying mechanisms of baicalin targeting in these lung diseases.

Baicalin attenuates amyloid β oligomers induced memory deficits and mitochondria fragmentation through regulation of PDE-PKA-Drp1 signalling

RATIONALE

Mitochondrial fragmentation contributes to the initiation of Alzheimer's disease (AD) pathology. Baicalin plays a significant role in rescuing mitochondrial dysfunction. However, the effect of baicalin treatment on the modulation of mitochondrial fragmentation has not yet been assessed.

OBJECTIVES

The present study was designed to evaluate the effect of baicalin on memory and understand its mechanism of action.

RESULTS

Baicalin treatment significantly reversed the altered learning and memory behaviours in AD mouse model. We found that baicalin treatment significantly improved the levels of microtubule association protein-2 and enhanced the expression of synaptophysin and postsynaptic density protein 95 (PSD95). Moreover, treatment with baicalin reversed amyloid-β oligomer (AβO)-induced abnormalities in the succinate dehydrogenase complex iron sulphur subunit B (SDHB) and cytochrome c oxidase components I (COXI) and mitochondrial fragmentation in the hippocampus. Further, we found that baicalin decreased the PDE4 levels and upregulated the levels of phosphorylated Ser157 site of vasodilator-stimulated phosphoprotein (pVASP^s157) and phosphorylated Ser637 site of mitochondrial dynamin-related protein 1 (pDrp1^S637). Moreover, in AβO-treated HT-22 cells, H89 inhibited the effect of baicalin on PSD95, mitochondrial fragmentation, SDHB and COXI, PDE4, pVASP^s157, and pDrp1^S637.

CONCLUSION

The effect of baicalin on memory improvement may be due to improved synaptic plasticity, mitochondrial fragmentation, and rescue of dysfunction via the inhibition of PDE4, which leads to activation of pDrp1^S637 in the AβO-induced model.

Genomics approaches to synthesize plant-based biomolecules for therapeutic applications to combat SARS-CoV-2

COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is devastative to the humankind for which neither vaccines nor precise therapeutic molecules for treatment are identified. The search for new drugs and repurposing of existing drugs are being performed; however, at the same time, research on plants to identify novel therapeutic compounds or testing the existing ones is progressing at a slower phase. In this context, genomics and biotechnology offer various tools and strategies to manipulate plants for producing those complex biopharmaceutical products. This review enumerates the scope for research on plant-based molecules for their potential application in treating SARS-CoV-2 infection. Strategies to edit gene and genome, overexpression and silencing approaches, and molecular breeding for producing target biomolecules in the plant system are discussed in detail. Altogether, the present review provides a roadmap for expediting research on using plants as a novel source of active biomolecules having therapeutic applications.

Anti-inflammatory action of herbal medicine comprised of Scutellaria baicalensis and Chrysanthemum morifolium

Abbreviations

JNK: c-Jun N-terminal kinases; COPD: chronic obstructive pulmonary disease; CM: Chrysanthemum morifolium; COX-2: cyclooxygenase-2; ERK: extracellular-signal-regulated kinase; IL-6: interleukin-6; IL-8: interleukin-8; IL-12: interleukin-12; LPS: lipopolysaccharide; MAPK: mitogen-activated protein kinase; NO: nitric oxide; NK- κB: nuclear factor kappa B; p38: p38 mitogen-activated protein kinases; PBS: phosphate buffered saline; PMA: phorbol-12-myristate-13-acetate; SB: Scutellaria baicalensis; PGE2: prostaglandin E2; TBST: Tris-buffered saline containing 0.1% Tween 20; TIC: total ion chromatogram; TNF-α: tumor necrosis factor-alpha

Use of Natural Products in Asthma Treatment

Asthma, a disease classified as a chronic inflammatory disorder induced by airway inflammation, is triggered by a genetic predisposition or antigen sensitization. Drugs currently used as therapies present disadvantages such as high cost and side effects, which compromise the treatment compliance. Alternatively, traditional medicine has reported the use of natural products as alternative or complementary treatment. The aim of this review was to summarize the knowledge reported in the literature about the use of natural products for asthma treatment. The search strategy included scientific studies published between January 2006 and December 2017, using the keywords "asthma," "treatment," and "natural products." The inclusion criteria were as follows: (i) studies that aimed at elucidating the antiasthmatic activity of natural-based compounds or extracts using laboratory experiments (in vitro and/or in vivo); and (ii) studies that suggested the use of natural products in asthma treatment by elucidation of its chemical composition. Studies that (i) did not report experimental data and (ii) manuscripts in languages other than English were excluded. Based on the findings from the literature search, aspects related to asthma physiopathology, epidemiology, and conventional treatment were discussed. Then, several studies reporting the effectiveness of natural products in the asthma treatment were presented, highlighting plants as the main source. Moreover, natural products from animals and microorganisms were also discussed and their high potential in the antiasthmatic therapy was emphasized. This review highlighted the importance of natural products as an alternative and/or complementary treatment source for asthma treatment, since they present reduced side effects and comparable effectiveness as the drugs currently used on treatment protocols.