In vitro evaluation of antioxidant, antineurodegenerative and antidiabetic activities of Ocimum basilicum L., Laurus nobilis L. leaves and Citrus reticulata Blanco peel extracts

Abstract

Ocimum basilicum (sweet basil) and Laurus nobilis (bay leaves or laurel) have been used in traditional medicine for centuries, and also extensively employed as spices for adding aroma and flavor to various food products. Citrus reticulata (mandarin) is mainly used in food industry for juice production, while its peel as main byproduct contains high concentration of valuable substances. The samples were collected in Lastva Grbaljska (Montenegrin coast) and purchased from the market. Since the oxidative stress results in development of numerous diseases, among them neurodegeneration and diabetes, the antioxidant activity, antineurodegenerative and antidiabetic activities were analyzed, aiming to compare potential of plants cultivated under natural conditions and commercially purchased from the market, as well as to compare the effect of different solvents applied in the extraction process. Water, methanol and acetone extracts of leaves and peel were tested by DPPH and total reducing power (TRP) methods for determination of antioxidant activity, and by acetylcholinesterase (AChE) and αglucosidase inhibition assays for analyzing the other activities. Total phenolic (TPC) and flavonoid (TFC) contents were also determined. The acetonic extract of L. nobilis from Lastva showed the highest TPC, DPPH, TRP, and α-glucosidase inhibition, while water extract of commercial L. nobilis exhibited the highest AChE inhibition. The leaves of L. nobilis are demonstrated to be promising antioxidant, antineurodegenerative and antidiabetic agent.

Assessing the In Vitro Inhibitory Effects on Key Enzymes Linked to Type-2 Diabetes and Obesity and Protein Glycation by Phenolic Compounds of Lauraceae Plant Species Endemic to the Laurisilva Forest

“…Previously [ 23 ], our research group reported PACs (A- and B-types) and flavonol glycosides as the main components of Apollonias barbujana , Laurus novocanariensis (laurel), Ocotea foetens and Persea indica ( Figure 2 ), the most relevant Lauraceae species of Laurissilva. The anti-diabetic effects of similar plants ( Laurus nobilis , Persea americana and Ocotea bullata ) have been documented before [ 3 , 5 , 13 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], and similar properties were expected for targeted Lauraceae species. Therefore, this study was designed to evaluate for the first time the in vitro inhibitory effects of four Lauraceae plant extracts ( A. barbujana , L. novocanariensis , O. foetens and P. indica ) on digestive enzymes linked to the carbohydrates (α-amylase, and α-glucosidase) and lipids metabolism (pancreatic lipase), aldose reductase and protein glycation.…”

“…Ocotea bullata bark extracts demonstrated high inhibition of carbohydrate-metabolizing enzymes [ 24 ]. Different extracts of L. nobilis (bay laurel) inhibited α-glucosidase metabolic activity [ 3 , 13 ]. L. nobilis effectively inhibited α-amylase, but Cinnamomum verum (true cinnamon) extract was much more effective [ 31 ].…”

“…[ 5 , 10 , 11 , 12 ]. The Lauraceae family comprises several plant species, some of high commercial value (including Laurus, Persea and Cinnamomum genera), due to their culinary, therapeutic, or industrial applications [ 13 ]. Cinnamon ( Cinnamomum spp.)…”

Plant-Based Antioxidants for Prevention and Treatment of Neurodegenerative Diseases: Phytotherapeutic Potential of Laurus nobilis, Aronia melanocarpa, and Celastrol

“…An analysis of the potential neuroprotective activity of various leaf extracts was performed in a study by Duletić-Laušević et al [ 47 ]. The highest AChE inhibition (%) was obtained by the water extract of commercial L. nobilis (90.72%), followed by acetonic and methanolic extracts.…”

“…The highest AChE inhibition (%) was obtained by the water extract of commercial L. nobilis (90.72%), followed by acetonic and methanolic extracts. Since the acetone extract of L. nobilis showed the highest antioxidant activity (total phenolic content, TPC) and α-glucosidase inhibition, while the water extract of commercial bay laurel exhibited the highest AChE inhibition, the bay leaves could be a promising antioxidant, neuroprotective, and antidiabetic agent [ 47 ].…”