Chemical analysis, biological and therapeutic activities of Olea europaea L. extracts

The Olea europaea L. is a very well-known and widely used plant, especially for its nutritional qualities. Its extracts from leaves and fruits are widely used in contrasting and preventing various pathologies. In this review, the collected data highlight important chemical analyses and biological effects of this plant extracts. It exhibits cholesterol-lowering, hypoglycemic, cytotoxic, antibacterial, neuroprotective, antioxidant, anti-inflammatory and hypotensive activities. The results show that extracts from O. europaea could be used as a food additive in the supplementary treatment of many diseases.

Indian Medicinal Plants and Formulations and Their Potential Against COVID-19-Preclinical and Clinical Research

The cases of COVID-19 are still increasing day-by-day worldwide, even after a year of its first occurrence in Wuhan city of China. The spreading of SARS-CoV-2 infection is very fast and different from other SARS-CoV infections possibly due to structural differences in S proteins. The patients with severe diseases may die due to acute respiratory distress syndrome (ARDS) caused by systemic inflammatory reactions due to the excessive release of pro-inflammatory cytokines and chemokines by the immune effector cells. In India too, it is spreading very rapidly, although the case fatality rate is below 1.50% (https://www.statista.com), which is markedly less than in other countries, despite the dense population and minimal health infrastructure in rural areas. This may be due to the routine use of many immunomodulator medicinal plants and traditional AYUSH formulations by the Indian people. This communication reviews the AYUSH recommended formulations and their ingredients, routinely used medicinal plants and formulations by Indian population as well as other promising Indian medicinal plants, which can be tested against COVID-19. Special emphasis is placed on Indian medicinal plants reported for antiviral, immunomodulatory and anti-allergic/anti-inflammatory activities and they are categorized for prioritization in research on the basis of earlier reports. The traditional AYUSH medicines currently under clinical trials against COVID-19 are also discussed as well as furtherance of pre-clinical and clinical testing of the potential traditional medicines against COVID-19 and SARS-CoV-2. The results of the clinical studies on AYUSH drugs will guide the policymakers from the AYUSH systems of medicines to maneuver their policies for public health, provide information to the global scientific community and could form a platform for collaborative studies at national and global levels. It is thereby suggested that promising AYUSH formulations and Indian medicinal plants must be investigated on a priority basis to solve the current crisis.

Oleuropein-Rich Olive Leaf Extracts May Ameliorate Consequences of Glucose-Induced Oxidative Stress in Hep G2 Cells

Olive leaf is reputed to have many beneficial health-related properties, often attributed to the iridoid glycoside oleuropein. In this work, the composition and antioxidant activity of oleuropein-rich olive leaf extracts prepared by ultrasonication were investigated. In addition, the influence of the extracts on Hep G2 cells subjected to glucose-induced oxidative stress was examined. The prepared extracts acted as antioxidants rich in oleuropein and other polyphenols. Among them, the extract prepared at 20°C using 100% ethanol was the most effective radical scavenger, antioxidant and metal chelator. It also contained the largest amount of oleuropein and other phenolic constituents. The extract prepared at 20°C using 70% ethanol, on the other hand, showed the best yield among the investigated extracts. Furthermore, it was able to preserve the cell-membrane integrity of Hep G2 cells subjected to glucose-induced oxidative stress, as well as to maintain intracellular concentration of glutathione and the activity of glutathione S-transferase on the levels comparable to those observed in non-stressed cells. The presented results demonstrate that oleuropein-rich olive leaf extracts can effectively ameliorate the consequences of glucose-induced oxidative stress in liver cells.