Vedrana Čikeš Čulić

Research background. The current changes in the global economy, characterised by the climate crisis and the economic and health impact of the COVID-19 pandemic, have led to a significant demand for medicinal herbs. This trend is expected to increase significantly by 2050. In this study, we investigated the biopotential of aqueous infusions of four medicinal plants: Calendula officinalis, Chelidonium majus, Teucrium chamaedrys and Alchemilla vulgaris. Experimental approach. The flavonoid analysis of the aqueous infusions of the selected plants was carried out using the RP-HPLC technique. The antiproliferative activity of the prepared aqueous plant infusions was analysed against three human cancer cell lines (MDA-MD-231, T24 and A549), while the antioxidant potential was measured using three antioxidant methods (DPPH, FRAP and Rancimat assay). Results and conclusions. T. chamaedrys had the highest total phenolics (expressed as GAE (2061±42) mg/L), free radical scavenging activity (IC50=1.9 mg/mL) and Fe(III) reducing antioxidant power (expressed as FeCl2 (9798±27) mg/L). At a concentration of 1 mg/mL, the antiproliferation of T24 by C. majus was 96 % and of MDA-MD-231 cells by A. vulgaris was 75 % after 72 h. After principal component analysis, T. chamaedrys and C. majus were grouped together. Quercetin glucoside and antioxidant capacity (DPPH) contributed the most to differentiate these infusions from the other two. Novelty and scientific contribution. This study represents a comparative analysis of the biopotential of four medicinal plants. A new RP-HPLC method was developed to separate the flavonoids in the herbal infusions. This is the first report on the presence of kaempferol-3-O-rutinoside in C. officinalis and isorhamnetin-3-O-rutinoside in A. vulgaris aqueous infusion. For the first time, C. majus has been shown to contribute to the oxidative stability of edible oil. Furthermore, this is the first comparative study on the antiproliferative activity of selected medicinal plants against the cell lines MDA-MD-231, T24 and A549.

This study was conducted to determine the differences in the chemical composition of the essential oils and hydrosols of six different Veronica species (V. agrestis, V. anagalloides, V. austriaca ssp. jacquinii, V. beccabunga, Veronica cymbalaria, and V. officinalis) and to test their antiproliferative and apoptotic activities, according to the authors’ knowledge, because of insufficient research and lack of information. Also, the goal was to determine which obtained samples were better in achieving antiproliferative and apoptotic activities and due to which volatile components. Therefore, essential oils (EOs) and hydrosols (HYs) were isolated from the above-mentioned Veronica species by microwave-assisted extraction (MAE). Phytochemical identification of the free volatile compounds was performed using a GC equipped with a flame ionization detector and a mass spectrometer. Their antiproliferative and apoptotic activities against two human cancer cell lines, breast cancer cell line MDA-MB-231 and bladder cancer cell line T24, were determined. The main compounds identified in the studied Veronica EOs and HYs were terpinen-4-ol (0.34–6.49%), linalool (0.34–6.61%), (E)-caryophyllene (0.97–7.55%), allo-aromadendrene (0.18–2.21%), caryophyllene oxide (1.42–23.83%), benzene acetaldehyde (0.26–13.34%), and β-ionone (1.08–16.53%). In general, HYs of the tested Veronica species showed higher antiproliferative activity (IC50 13.41–42.05%) compared to EOs (IC50 158.1–970.4 µg/mL) on MDA-MB-231 and T24 cancer cell lines after 48 and 72 h. V. agrestis EO showed the best apoptotic effect among the EOs on the MDA-MB-231 cancer cell line (10.47 ± 0.53% and 9.06 ± 0.74% of early/late apoptosis, compared with control 3.61 ± 0.62% and 0.80 ± 0.17% of early/late apoptosis, respectively) and among the HYs V. cymbalaria showed 9.95 ± 1.05% and 3.06 ± 0.28% of early/late apoptosis and V. anagalloides 8.29 ± 1.09% and 1.95 ± 0.36% of early/late apoptosis compared with control (for EO was 7.45 ± 1.01% and 0.54 ± 0.25%, and for HY was 4.91 ± 1.97% and 0.70 ± 0.09% of early/late apoptosis, respectively) on the T24 cancer cell line. Future research will include other Croatian species of the genus Veronica to gain a more complete insight into the biological activity of the volatile products of this genus for potential discovery of drugs based on natural plant extracts.

Helichrysum italicum (Roth) G. Don., immortelle, is a plant species used in ethnomedicine and the food industry as a spice added to food, beverages, and bakery products. It has been shown to possess various biological activities, such as antioxidant and antibacterial activity, making it useful as a natural preservative. We investigated the phytochemical profile and biological activity of H. italicum essential oils from wild-grown plant material collected from natural habitats in the Republic of Croatia and Bosnia and Herzegovina. Using high-resolution scanning electron microscopy (SEM), a visual investigation of plant organs (stem, leaf, and flower) was performed, confirming the presence of essential oil reservoirs on the surface of all examined plant organs. Essential oils were isolated by hydrodistillation in the Clevenger apparatus. The chemical composition of the essential oils was determined using the GC-MS analytical technique. Cytotoxic activity tests were performed in vitro on three cell lines: skin (fibroblast), lung, and breast cancer. Using statistical tools, the synergistic and selective effects of H. italicum essential oil on healthy and tumor cells were correlated to chemical composition and cytotoxic activity. The synergistic and antagonistic effects of H. italicum essential oil’s individual components were simulated by testing pure compounds and their mixture of cytotoxic activity on fibroblasts and breast cancer cells. The results confirm that essential oil’s biological activity is much greater than the sum of the effects of its components. The present data are novel contributions to the body of knowledge on the biological activity of this species used in the food industry.

Nerolidol is a naturally occurring sesquiterpene alcohol with multiple properties, including antioxidant, antibacterial, and antiparasitic activities. A few studies investigating the antitumor properties of nerolidol have shown positive results in both cell culture and mouse models. In this study, we investigated the antitumor mechanism of cis-nerolidol in bladder carcinoma cell lines. The results of our experiments on two bladder carcinoma cell lines revealed that nerolidol inhibited cell proliferation and induced two distinct cell death pathways. We confirmed that cis-nerolidol induces DNA damage and ER stress. A mechanistic study identified a common cAMP, Ca2+, and MAPK axis involved in signal propagation and amplification, leading to ER stress. Inhibition of any part of this signaling cascade prevented both cell death pathways. The two cell death mechanisms can be distinguished by the involvement of caspases. The early occurring cell death pathway is characterized by membrane blebbing and cell swelling followed by membrane rupture, which can be prevented by the inhibition of caspase activation. In the late cell death pathway, which was found to be caspase-independent, cytoplasmic vacuolization and changes in cell shape were observed. cis-Nerolidol shows promising antitumor activity through an unorthodox mechanism of action that could help target resistant forms of malignancies, such as bladder cancer.