Oral submucous fibrosis (OSF) is characterized by abnormal collagen deposition. It is a precancerous disorder and transforms into a malignant tumor in 1.5–15% of all cases. Symptoms include submucous fibrosis, ulceration, xerostomia, a burning sensation, and restricted mouth opening. All of these greatly interfere with patient quality of life. The present review introduces OSF from a molecular perspective and summarizes what is known about its underlying mechanisms, diagnostic biomarkers, and therapeutic interventions. In addition to the aggressive treatment of OSF, its prevention is also important. Future research should, therefore, focus on improving the oral health literacy of the patients susceptible to OSF.

Around 200–600 million Asians chew areca (also called betel), which contains a mixture of areca nut and other ingredients. Epidemiological evidences indicated that areca use is tightly linked to oral carcinogenesis. This study investigated the effects of ripe areca nut extract (ANE) on cultured normal human oral keratinocyte (NHOK). Acute subtoxic ANE treatment inhibited DNA synthesis and induced cell cycle arrest at G ₁ phase in early passage (<4th passage) cells. This was accompanied by a slight increase in the sub-G ₁ cellular fraction. O (6)-Methylguanine-DNA methyltransferase (MGMT), Hsp27 and p38MAPK was upregulated. p16 and p21 were remarkably upregulated early and declined afterwards. In contrast, the increase of dephosphorylated Rb seemed to be secondary to the episodes of p16 and p21 upregulation. To simulate the chronic areca exposure in vivo , constant ANE treatment in serial NHOK culture was performed. It resulted in a significant decrease in the population doubling, increase in senescence-associated β-galactosidase (SA-β-Gal) and decrease in cell proliferation in NHOK of late passages (≥4th passage). Induction of senescence-associated phenotypes, G ₂ /M accumulation and genomic instability following long-term ANE treatment were also observed in a low-grade oral carcinoma cell. ANE-treated NHOK also had a higher nuclear factor-κB (NF-κB) fraction and a lower cytosolic IκBα level relative to the control in late passages. Moreover, electrophoretic mobility shift assay (EMSA) indicated that ANE treatment shifted the NF-κB complex from high mobility position to lower mobility position in late-passaged NHOK. ANE treatment also upregulated IL-6 and cyclooxygenase-2 ( COX-2 ) mRNA expressions in late-passaged NHOK. In summary, our findings suggest that ANE induces the cell cycle arrest at G ₁ /S phase and the occurrence of senescence-associated phenotypes of NHOK. The upregulation of p38MAPK, p16, p21, NF-κB, IL-6 and COX-2 are likely to participate in the control of these impacts.

The etiological factors of oral cancer are complex including drinking alcohol, smoking tobacco, betel quid chewing, human papillomavirus infection, and nutritional deficiencies. Understanding the molecular mechanism of oral cancer is vital. The traditional treatment for patients with oral squamous cell carcinoma (e.g., surgery, radiotherapy, and chemotherapy) and targeted molecular therapy still have numerous shortcomings. In recent years, the use of phytochemical factors to prevent or treat cancer has received increasing attention. These phytochemicals have little or no toxicity against healthy tissues and are thus ideal chemopreventive agents. However, phytochemicals usually have low water solubility, low bioavailability, and insufficient targeting which limit therapeutic use. Numerous studies have investigated the development of phytochemical delivery systems to address these problems. The present article provides an overview of oral cancer including the etiological factors, diagnosis, and traditional therapy. Furthermore, the classification, dietary sources, anticancer bioactivity, delivery system improvements, and molecular mechanisms against oral cancer of phytochemicals are also discussed in this review.

The spike glycoprotein on the virion surface docking onto the angiotensin‐converting enzyme (ACE) 2 dimer is an essential step in the process of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection in human cells—involves downregulation of ACE2 expression with systemic renin‐angiotensin system (RAS) imbalance and promotion of multi‐organ damage. In general, the RAS induces vasoconstriction, hypertension, inflammation, fibrosis, and proliferation via the ACE/Ang II/Ang II type 1 receptor (AT1R) axis and induces the opposite effects via the ACE2/Ang (1‐7)/Mas axis. The RAS may be activated by chronic inflammation in hypertension, diabetes, obesity, and cancer. SARS‐CoV‐2 induces the ACE2 internalization and shedding, leading to the inactivation of the ACE2/Ang (1‐7)/Mas axis. Therefore, we hypothesize that two hits to the RAS drives COVID‐19 progression. In brief, the first hit originates from chronic inflammation activating the ACE/Ang II/AT1R axis, and the second originates from the COVID‐19 infection inactivating the ACE2/Ang (1‐7)/Mas axis. Moreover, the two hits to the RAS may be the primary reason for increased mortality in patients with COVID‐19 who have comorbidities and may serve as a therapeutic target for COVID‐19 treatment.

Acute lung injury (ALI) is a high mortality disease with acute inflammation. Corylin is a compound isolated from the whole plant of Psoralea corylifolia L. and has been reported to have anti-inflammatory activities. Herein, we investigated the therapeutic potential of corylin on lipopolysaccharides (LPS)-induced ALI, both in vitro and in vivo. The levels of proinflammatory cytokine secretions were analyzed by ELISA; the expressions of inflammation-associated proteins were detected using Western blot; and the number of immune cell infiltrations in the bronchial alveolar lavage fluid (BALF) were detected by multicolor flow cytometry and lung tissues by hematoxylin and eosin (HE) staining, respectively. Experimental results indicated that corylin attenuated LPS-induced IL-6 production in human bronchial epithelial cells (HBEC3-KT cells). In intratracheal LPS-induced ALI mice, corylin attenuated tissue damage, suppressed inflammatory cell infiltration, and decreased IL-6 and TNF-α secretions in the BALF and serum. Moreover, it further inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs), including p-JNK, p-ERK, p-p38, and repressed the activation of signal transducer and activator of transcription 3 (STAT3) in lungs. Collectively, our results are the first to demonstrate the anti-inflammatory effects of corylin on LPS-induced ALI and suggest corylin has significant potential as a novel therapeutic agent for ALI.