Phytochemicals and Cytotoxicity of Quercus infectoria Ethyl Acetate Extracts on Human Cancer Cells

Conventional and modern cancer treatment were reported to manifest adverse effects to the patients. More researches were conducted to search for selective cytotoxic agent of plant natural product on cancer cells. The presences of wide range phytochemicals in Quercus infectoria (QI) extract have been implicated with the cytotoxic effect against various types of cancer cell which remain undiscovered. This present study aimed to evaluate cytotoxic effect of QI extracts on selected human cancer cells and then, the most potent extract was further analysed for general phytochemical constituents. QI galls were extracted successively with n-hexane, ethyl acetate and methanol yielded three main extracts; n-hexane (QIH), ethyl acetate (QIEA) and methanol (QIM), respectively. The most potent extract was qualitatively analysed for the present of tannin, alkaloids, glycosides, saponins, terpenoids, flavonoids and phenolic compounds. Next, the extracts were tested to determine the cytotoxic activity against cervical cancer cells (HeLa), breast cancer cells (MDA-MB-231) and liver cancer cells (Hep G2) using MTT assay. Cytotoxic activity of QI extracts against normal fibroblast (L929) cell line was also evaluated to determine the cytoselective property. Meanwhile, DMSO-treated cells served as negative control while cisplatin-treated cells served as positive control. The most potent extract then chosen to be further investigated for DNA fragmentation as hallmark of apoptosis using Hoechst staining. Qualitative phytochemical analysis revealed the presence of tannin, alkaloids, glycosides, saponins, terpenoids, flavonoids and phenolic compounds. QIEA extract exhibited the most potent cytotoxic activity against HeLa cells with (IC₅₀ value = 6.33 ± 0.33 μg/mL) and showed cytoselective property against L929 cells. DNA fragmentation revealed QIEA induced apoptosis in the treated cells. The richness of phytochemical constituents in QIEA extract might contribute to the potency of cytotoxic activity towards HeLa cells.

Rawatan kanser secara moden dan tradisional dilaporkan telah memberi kesan sampingan kepada pesakit. Banyak kajian telah dijalankan untuk mencari agen sitotoksik yang hanya mensasarkan sel kanser menggunakan produk semulajadi daripada sumber tumbuh-tumbuhan. Kewujudan bahan fitokimia yang pelbagai dalam ekstrak Quercus infectoria (QI) memberi kesan toksik terhadap beberapa jenis sel kanser yang belum terungkai. Kajian ini bertujuan untuk menilai aktiviti sitotoksik beberapa jenis ekstrak dan memilih ekstrak yang paling poten untuk dianalisa bahan fitokimia secara umum. Ketuat QI diekstrak secara berperingkat menggunakan n-heksana, etil asetat dan methanol menghasilkan ekstrak: n-heksana (QIH), etil asetat (QIEA) dan methanol (QIM) masing-masing. Ekstrak yang paling poten dianalisis secara kualitatif untuk menentukan kehadiran tanin, alkaloids, glikosida, saponin, terpenoid, flavonoid dan sebatian fenolik. Seterusnya setiap ekstrak diuji aktiviti sitotoksik terhadap sel kanser servik, (HeLa), sel kanser mamari (MDA-MB-231) dan sel kanser hati (Hep G2) menggunakan cerakinan MTT. Aktiviti sitotoksik ekstrak QI juga diuji ke atas sel fibroblast normal (L929) untuk menentukan ciri selektifnya. Sel yang dirawat dengan DMSO bertindak sebagai kawalan negatif, manakala sel yang dirawat dengan sisplatin bertindak sebagai kawalan positif. Ekstrak yang paling poten seterusnya dipilih untuk menyelidik fragmentasi DNA sebagai tanda berlaku apoptosis menggunakan pewarnaan Hoechst. Analisis kualitatif menunjukkan kehadiran tanin, alkaloids, glikosida, saponon, terpenoids, flavonoid dan sebatian fenolik. Ekstrak QIEA adalah paling poten terhadap sel HeLa (IC₅₀ = 6.33 ± 0.33 μg/mL) dan menunjukkan ciri sitoselektif terhadap sel L929. Fragmentasi DNA membuktikan QIEA mengaruh apoptosis dalam sel yang dirawat. QIEA yang kaya dengan bahan fitokimia kemungkinan menyumbang kepada kepotenan aktiviti sitotoksik terhadap sel HeLa.

Keywords: Aktiviti sitotoksik; Ciri sitoselektif; Cytoselective; Cytotoxic activity; DNA fragmentation; Ekstrak Quercus infectoria; Fragmentasi DNA; Kandungan fitokimia; Phytochemical constituents; Quercus infectoria extracts.