ABSTRACT
Background: Melissa officinalis L. (MO), commonly known as lemon balm, a member of the mint family, is considered a calming herb. In various traditional medicines, it has been utilized to reduce stress and anxiety and promote sleep. A growing body of clinical evidence suggests that MO leaf extract supplementation possesses considerable neuropharmacological properties. However, its possible mechanism of action largely remains unknown. Objective: In the present in vitro studies, we comparatively investigated the central nervous system (CNS)-calming and antioxidative stress properties of an innovative standardized phospholipid carrier-based (Phytosome™) MO extract (Relissa™) vs. an unformulated dry MO extract. Methods: The neuropharmacological effect of the extract was studied in the anti-depressant enzymes γ-aminobutyrate transaminase (GABA-T) and monoamine oxidase A (MAO-A) assays and SH-SY5Y cells brain-derived neurotrophic factor (BDNF) expression assay. The neuroprotective effect of the extract against oxidative stress was assessed in SH-SY5Y cell-based (H2O2-exposed) Total Antioxidant Status (TAS) and Total Reactive Oxygen Species (ROS) assays. The cytotoxic effect of the extract was evaluated using MTT and LDH assays. The extract antioxidant effect was also evaluated in cell-free chemical tests, including TEAC-ABTS, DPPH, Ferric Reducing Antioxidant Power (FRAP), Oxygen Radical Antioxidant Capacity (ORAC), and Hydroxyl Radical Antioxidant Capacity (HORAC) assays. Results: Relissa™ exhibited high GABA-T inhibitory activity, IC50 (mg/mL) = 0.064 vs. unformulated dry MO extract, IC50 (mg/mL) = 0.27. Similar inhibitory effects were also observed for MAO-A. Relissa™ demonstrated an improved neuroprotective antioxidant effect on SH-SY5Y cells against H2O2-induced oxidative stress. Compared to unformulated dry MO extract, Relissa™ exerted high protective effect on H2O2-exposed SH-SY5Y cells, leading to higher cells BDNF expression levels. Moreover, cell-free chemical tests, including TEAC-ABTS, DPPH radical scavenging, FRAP, ORAC, and HORAC assays, validated the improved antioxidant effect of Relissa™ vs. unformulated dry MO extract. Conclusion: The results of the present study support the neuromodulating and neuroprotective properties of Relissa™, and its supplementation may help in the amelioration of emotional distress and related conditions.
ABSTRACT
In anticancer therapy, the effectiveness of therapeutics is limited by mutations causing drug resistance. KRAS mutations are the only determinant for cetuximab resistance in patients with colorectal cancer (CRC). However, cetuximab treatment has not been fully successful in the majority of patients with wild-type (WT) KRAS. Therefore, it is important to determine new predictive mutations in CRC treatment. In the present study, the association between AKT1/ß-catenin (CTNNB1) mutations with the drug resistance to cetuximab and other chemotherapeutics used in the CRC treatment was investigated by using site-directed mutagenesis, transfection, western blotting and cell proliferation inhibition assay. Cetuximab resistance was higher in the presence of AKT1 E17K, E49K and L52R mutations, as well as CTNNB1 T41A, S45F and S33P mutations compared with that of respective WT proteins. AKT1/CTNNB1 mutations were also associated with oxaliplatin, irinotecan, SN-38 and 5-fluorouracil resistance. Furthermore, mutant cell viability in oxaliplatin treatment was more effectively inhibited compared with that of the other chemotherapeutic drugs. In conclusion, AKT1/CTNNB1 mutations may be used as an important predictive biomarker in CRC treatment.
