ABSTRACT
Artemisinin, the main active compound in Artemisia annua L., has been used for antimalarial properties for centuries and currently attracting increasing interest for its antiviral activities. In addition, several recent publications indicated that this valuable compound can be effective on Sars-CoV-2 virus. In the study, a high-performance liquid chromatography (HPLC) method was optimized in terms of mobile phase compositions, column temperature and flow rate using response surface methodology for the determination of artemisinin from A. annua samples. The method was also validated for some parameters according to the Eurachem guideline. Validated method was applied on A. annua plant samples, cultivated in a controlled condition, and content of artemisinin was found in the range from 5825 to 7972 mg/kg (n = 20). Extraction conditions of artemisinin from the plant samples were also optimized. In the first step of the extraction, solvents with different polarities were applied to the samples for the evaluation of artemisinin solubility. Then, ethanol was chosen for extraction solvent due the high extraction yield and classification in safer chemical ingredients list by EPA. After the extraction, a purification step using various adsorbents was studied to remove remnant impurities such as chlorophyl. The results showed that powdered charcoal was found to be the most effective adsorbent. Amount of the adsorbent was also studied to evaluate for the reduction of chlorophyl without reducing the artemisinin concentration. Finally, purified solvent was dewaxed, evaporated, and dried under nitrogen to concentrate the artemisinin content. In conclusion, the optimized conditions could be regarded as a new alternative technique in pharmaceutical industry for the extraction of artemisinin from A. annua samples. © 2022 Elsevier GmbH
ABSTRACT
OBJECTIVE: In this period when mutant strains are increasing all over the world, studies on how much humoral immunity will protect against the Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) are quite limited. The aim of our study is to investigate the positivity and antibody levels of the COVID-19 reverse transcription polymerase chain reaction (RT-PCR) test, the frequency of SARS-CoV-2 re-infection, and the protective antibody level against re-infection. METHODS: Patients who were positive for COVID-19 IgG antibody between 1 July and 31 August were included in our study. The COVID-19 RT-PCR test positivity, age, gender and comorbidities of these patients were recorded before this date. The COVID-19 RT-PCR test positivity of these patients was followed from the National COVID-19 Database between September 1, 2020 and February 28, 2021. RESULTS: 1665 patients (female: male 683: 982, mean age 40.6+/-13.4 years). Among all patients, 14 patients had reinfection and the frequency of reinfection was 0.8%. It was observed that the frequency of reinfection was more frequent in patients with PCR negative (p<0.001). The IgG cut-off value causing reinfection was found to be 11.9 (AUC: 0.844, 79.2% sensitivity, 78.6% specificity) (p<0.001). CONCLUSION: Humoral antibodies against SARS-CoV-2 were protective against COVID-19 reinfection, 0.8% of the patients had reinfection and the resultant reinfection was mostly seen in PCR negative patients who were asymptomatic.
ABSTRACT
SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) belongs to the beta coronavirus family and shows an important global spread that is forcing the worldwide health care capacity, economic and social public life. It was referred that this deadly infection (COVID-19) has resulted in more than 1 million deaths and a lot of multiorgan failure around the world. The virus seriously affected people of old age, chronic cardiac problems, chronic respiratory syndromes, and hypertension. But in some cases, the disease may have a moderate or asymptomatic indication. Oxidative stress occurs because of an imbalance in the organism between the formation of the oxidizing system and antioxidant mechanisms. After the production of free radicals, antioxidant enzymes such as glutathione, melatonin, quercetin, curcumin, and vitamins, play an important role in neutralizing the effects of free radicals. The imbalance of oxidative stress and accumulating free radicals may get involved in the formation of cancers, degenerative diseases, hypertension, diabetes mellitus, heart and vessel diseases, and virus infections, especially RNA viruses like HIV 1, SARS, MERS, and coronaviruses. A common approach in COVID-19 infection is the disruption of the antioxidant balance so free radicals can be exposed and accumulate in the organism. The depletion of the glutathione content, which is the most common antioxidant molecule of the tissues, causes the organism to increase the inflammation. In this article, we will discuss the role of free radical mechanisms in the formation of infection by COVID-19 and the treatment of the disease by different antioxidants such as GSH, melatonin, vitamins (C, D, E, A), and food additives. © 2021 Nova Science Publishers, Inc.