Peperomia pellucida (L.) Kunth and eye diseases: A review on phytochemistry, pharmacology and toxicology / 中西医结合学报

Peperomia pellucida (L.) Kunth is a medicinal plant used to manage inflammatory illnesses such as conjunctivitis, and gastrointestinal and respiratory tract disorders in tropical and subtropical regions. However, little is known about its pharmacological mechanism of action against eye diseases. This review aims to critically discuss the phytochemistry, pharmacology and toxicology of P. pellucida as well as its roles in the treatment of cataract, glaucoma and diabetic retinopathy. Recent developments in the uses of P. pellucida for healthcare and nutraceutical products by the pharmaceutical industry are also covered in this review. For this review, a literature search was performed with PubMed, ScienceDirect, SciFinder Scholar and Scopus databases, using relevant keywords. Among the various phytochemicals identified from P. pellucida, β-caryophyllene, carotol, dillapiole, ellagic acid, pellucidin A, phytol and vitexin exhibit strong pharmacological activities within the mitogen-activated protein kinase and nuclear factor-κB signalling pathways in inflammatory eye diseases. The antihypertensive, anti-inflammatory, antioxidant, antihyperglycemic and anti-angiogenic activities displayed by P. pellucida extracts in many in vitro, in vivo and clinical studies suggest its potential role in the management of inflammatory eye diseases. P. pellucida extract was non-toxic against normal cell lines but displayed mild toxicity in animal models. The growing public interest in P. pellucida has inspired the nutraceutical and pharmaceutical industries to process the plant into health products. Although the potential pharmacological mechanisms against eye diseases have been summarized, further studies of the interactions among constituent phytochemicals from P. pellucida within various signalling pathways shall support the use of the plant as an alternative therapeutic source.

Mitochondrial neurogastrointestinal encephalomyo pathy (MNGIE) in a Malaysian patient with a novel mutation in thymidine phosphorylase gene: A case report

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare neurodegenerative multisystem disorder inherited in an autosomal recessive manner and characterized clinically by gastrointestinal dysmotility, cachexia, ophthalmoparesis and/or ptosis, peripheral neuropathy and leukoencephalopathy. Heterogenous causative mutations in the thymidine phosphorylase (TP) gene located on chromosome 22q13 have been identifi ed. This is the fi rst reported case of a 25-year-old Malaysian patient, of indigenous Bajau ethnicity who presented with recurrent abdominal pain before developing other clinical features of classical MNGIE. Biochemical correlates include elevated plasma levels of thymidine, deoxyuridine and lactate. The brain MRI showed diffuse leucoencephalopathy while nerve conduction studies were consistent with demyelinating polyneuropathy. Direct DNA sequencing of the nine coding exons of the TP gene showed both a novel and a previously described mutation. The former is a point mutation in exon 5 (NG_011860.1:g.7387C>T) at amino acid position 179, resulting in a stop codon and premature truncation of thymidine phosphorylase(TP) protein while the latter mutation occurred at exon 10 (NG_011860.1:g.9279C>T) resulting in a missense homozygous mutation at amino acid position 471. Defi nite diagnosis was based on clinical features, plasma and urinary nucleosides and the identifi cation of mutations in the TP gene. This case report adds to the knowledge of genotype-phenotype relationship of TP mutations and its occurrence among ethnic groups worldwide.