The Analyses of Chemical Components From Oldenlandia hedyotidea (DC.) Hand.-Mazz and Anticancer Effects in vitro

Abstract

Oldenlandia hedyotidea (DC.) Hand.-Mazz (OH), also known as sweet tea, is a valuable functional food with medicinal properties and is used for the treatment of cold, cough, gastroenteritis, heatstroke, herpes zoster, and rheumatoid arthritis. The phytochemicals in plant-based foods are responsible for the occurrence of these diseases to some extent. However, there is a scarcity of information on the chemical components of OH. We, therefore, aimed to investigate the phytochemical components of OH using ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS) and UHPLC triple time-of-flight mass spectrometry (UHPLC-Triple-TOF-MS). The main component of the OH extract, asperulosidic acid, was additionally quantified using UHPLC with ultraviolet detection (UHPLC-UV). The anticancer activity of the OH extract was assessed by a cell proliferation assay and a scratch assay using an esophageal cancer cell line. Ten compounds were tentatively identified in the aqueous extract of OH, including five iridoids, two anthraquinones, and one phenolic acid. The content of asperulosidic acid in the aqueous extract of OH was approximately 42 μg ml^-1, and the extract exerted definite in vitro anticancer effects. The results can be used for quality control and assessment of the OH extract, which can serve as a promising source of functional ingredients for potential use in the food and drug industries.

Keywords: Oldenlandia hedyotidea (DC.) Hand.-Mazz; UHPLC-MS; UHPLC-Triple-TOF-MS; fingerprint; migration; proliferation.

FIGURE 1

Optimization of extraction solvents and total ion chromatography (TIC) using UHPLC-MS. (A) Comparison of OH dissolved in different solvents: 50% MeOH (pink), 75% MeOH (green), 100% MeOH (fuchsin), EtOH (blue), and Water (brown). (B) TIC in the negative ionization mode of OH dissolved by water.

FIGURE 2

Parent ion spectrums of the main ingredients. (A) Monotropein. (B) Deacetylasperulosidic acid. (C) 6,7-dihydroxy-7-(hydroxymethyl)-1-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)-1,4a,7,7a-tetrahydrocyclopenta [c]pyran-4-carboxylic acid. (D) 3-hydroxy-4-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-((sulfooxy)methyl)tetrahydro-2H-pyran-2-yl)oxy)benzoic acid. (E) Asperulosidic acid. (F) Scandoside. (G) Asperuloside. (H) Hedanthroside C. (I) Hedanthroside B. (J) Ferulic acid.

FIGURE 3

Chemical structures identified in OH. 1) Monotropein. 2) Deacetylasperulosidic acid. 3) 6,7-dihydroxy-7-(hydroxymethyl)-1-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)-1,4a,7,7a-tetrahydrocyclopenta [c]pyran-4-carboxylic acid. 4) 3-hydroxy-4-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-((sulfooxy)methyl)tetrahydro-2H-pyran-2-yl)oxy)benzoic acid. 5) Asperulosidic acid. 6) Scandoside. 7) Asperuloside. 8) Hedanthroside C. 9) Hedanthroside B. 10) Ferulic acid.

FIGURE 4

MS/MS spectra (A) and the proposed fragmentation pathway (B) of asperulosidic acid.

FIGURE 5

UHPLC fingerprints analysis and hierarchical cluster analysis. (A) The UHPLC fingerprints of 19 batches of OH samples (S1–S19) and reference standard fingerprint (R). C1—Monotropein. C2—Deacetylasperulosidic acid. C3—6,7-dihydroxy-7-(hydroxymethyl)-1-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)-1,4a,7,7a-tetrahydrocyclopenta [c]pyran-4-carboxylic acid. C4—3-hydroxy-4-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-((sulfooxy)methyl)tetrahydro-2H-pyran-2-yl)oxy)benzoic acid. C5—Asperulosidic acid. C6—Scandoside. C7—Hedanthroside C. C8—Hedanthroside B. C9—Ferulic acid. (B) Clustering analysis graph of the 19 batches of OH.

FIGURE 6

Water extract from OH inhibits migration and growth in the line of the esophageal cancer cell (EC109, KYSE140, KYSE410, and KYSE510). (A) The migration rate was measured by the wound healing assay. (B) Comparison of different doses of the water extract of OH on cell viability using the CCK-8 assay. Error bars represent SD (standard deviation), *indicates a difference compared with the PCG 1 group. *p < 0.1, **p < 0.01, ***p < 0.001, and ****p < 0.0001. ^# indicates a difference compared with the PCG 2 group. ^# p < 0.1, ^## p < 0.01, ^### p < 0.001, and ^#### p < 0.0001.