Lesser Burdock (Arctium minus) and Cancer (anticancer research): evidence and sources

Arctium minus (Hill) Bernh., commonly known as "Burdock", is a species within the Arctium genus of the Asteraceae family. Determining the optimum extraction conditions to obtain a concentrated extract with targeted active ingredients guides the most efficient use of natural products. Herein, ultrasound-assisted extraction (UAE) was optimized by using response surface methodology (RSM) to extract bioactive compounds from different organs of A. minus . Furthermore, phytochemical composition of extracts of the A. minus was investigated by using liquid chromatography-high resolution electrospray ionization mass spectrometry (LC-HRESIMS), antioxidant potential by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), diazanium;3-ethyl-2-[(3-ethyl-6-sulfonato-1,3-benzothiazol-2-ylidene)hydrazinylidene]-1,3-benzothiazole-6-sulfonate (ABTS), CUPRAC, and metal chelation assays, and cytotoxic activities by using human breast cancer cell line (MDA-MB-231) and hepatocellular carcinoma cancer cell line (HepG2), and compared against conventional methods; Soxhlet and maceration. The RSM was employed to investigate the influence of ultrasound power, extraction time, and extraction temperature on the antioxidant potential assessed by the DPPH free radical scavenging assay. In UAE of A. minus leaves, flowers, and branches, the conditions resulting in the minimum IC 50 values: 20 °C for 6 min at 50 W for leaves, 20 °C for 3 min at 100 W for flowers, and 20 °C for 3 min at 100 W for branches. Chlorogenic acid was identified as the major phenolic compound in the extracts obtained by UAE, with concentrations of 24,666.96 μg/g in leaves, 1054.92 μg/g in flowers, and 3,501.24 μg/g in branches. Flowers of A. minus had significantly higher levels of arctiin and arctigenin than those of leaves and branches. Extracts from leaves and flowers were more effective against MDA-MB-231 and HepG2 cancer cell lines than arctiin and arctigenin.

Arctium minus (Hill) Bernh. (Asteraceae), which has a wide distribution area in Turkey, is a medicinally important plant. Eighty percent methanol extracts of the leaf, flower head, and root parts of A. minus were prepared and their sub-fractions were obtained. Spectrophotometric and chromatographic (high-performance liquid chromatography) techniques were used to assess the phytochemical composition. The extracts were evaluated for antioxidant activity by diphenyl-2-picrylhydrazil radical (DPPH ● ), 2,2'-Azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS ●+ ) radical scavenging, and β-carotene linoleic acid bleaching assays. Furthermore, the extracts were subjected to α-amylase, α-glucosidase, lipoxygenase, and tyrosinase enzyme inhibition tests. The cytotoxic effects of extracts were investigated on MCF-7 and MDA-MB-231 breast cancer cell lines. The richest extract in terms of phenolic compounds was identified as the ethyl acetate sub-fraction of the root extract (364.37 ± 7.18 mg GAE /g extact ). Furthermore, chlorogenic acid (8.855 ± 0.175%) and rutin (8.359 ± 0.125%) were identified as the primary components in the leaves' ethyl acetate sub-fraction. According to all methods, it was observed that the extracts with the highest antioxidant activity were the flower and leaf ethyl acetate fractions. Additionally, ABTS radical scavenging activity of roots' ethyl acetate sub-fraction (2.51 ± 0.09 mmol/L Trolox) was observed to be as effective as that of flower and leaf ethyl acetate fractions at 0.5 mg/mL. In the β-carotene linoleic acid bleaching assay, leaves' methanol extract showed the highest antioxidant capacity (1422.47 ± 76.85) at 30 min. The enzyme activity data showed that α-glucosidase enzyme inhibition of leaf dichloromethane extract was moderately high, with an 87.12 ± 8.06% inhibition value. Lipoxygenase enzyme inhibition was weakly detected in all sub-fractions. Leaf methanol extract, leaf butanol, and root ethyl acetate sub-fractions showed 99% tyrosinase enzyme inhibition. Finally, it was discovered that dichloromethane extracts of leaves, roots, and flowers had high cytotoxic effects on the MDA-MB-231 cell line, with IC50 values of 21.39 ± 2.43, 13.41 ± 2.37, and 10.80 ± 1.26 µg/mL, respectively. The evaluation of the plant extracts in terms of several bioactivity tests revealed extremely positive outcomes. The data of this study, in which all parts of the plant were investigated in detail for the first time, offer promising results for future research.

Ethnopharmacological relevance Traditional medicine of the Native Americans has a long tradition of medicinal plants, which also influenced modern oncology. For instance, podophyllotoxin the active ingredient of Podophyllum peltatum L. (Berberidaceae) used by Native Americans to treat warts led to the development of etoposide and teniposide. In the present investigation, we studied 10 medicinal plants used by the Gwich׳in First Nation of West-Canada, which have been used against diverse diseases including cancer. Material and methods Sensitive and multidrug-resistant (MDR) tumor cell lines expressing various ATP-binding cassette (ABC) transporters (P-glycoprotein/ABCB1/MDR1, MRP1/ABCC1, or BCRP/ABCG2) have been used. Cytotoxicity was determined by the resazurin assay. Results Arctium minus Bernh. (Asteraceae). Lysichiton americanus Hultén & St. John (Araceae), and Maianthemum dilatatum (Alph.Wood) A.Nelson & J.F.Macbr.(Asparagaceae) were cytotoxic with IC50 values ranging from 2.40 to 86.35 µg/mL. The MDR cell lines did not exert cross-resistance to these extracts. Conclusion As these medicinal plants of the West-Canadian Gwich׳in First Nation were not involved in classical drug resistance mechanisms and might therefore be valuable to bypass anticancer drug resistance in refractory tumors.