BSc - MSc (Int.)

The research work entitled “Characterization and evaluation of anticancerous
property of stingless bee (Tetragonula travancorica) honey on breast and cervical
cancer cell lines” was carried out at College of Agriculture, Vellayani,
Thiruvananthapuram, during the year 2020 to 2021. The objective of the study was
to characterize stingless bee (T. travancorica) honey and to identify its anticancerous
property on breast and cervical cancer cell lines.
In the current study, characterization of stingless bee honey (SBH) and Indian
bee honey (IBH) was done using liquid chromatography-mass spectrometry (LCMS)
and ultraviolet visible (UV-VIS) spectrum analysis. Total phenol and flavonoid
content in honeys were determined using folin–ciocalteau colorimetric reagent
(FCR) method and aluminium chloride method respectively. The antioxidant activity
was measured using DPPH (1, 1, -diphenyl-2- picrylhydrazyl), ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid)and SOD (superoxide dismutase) radical
scavenging assays. The anti-proliferative properties were assessed on different
cancer and normal cell lines by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-
diphenyltetrazolium bromide) assay and trypan blue dye exclusion method. Proteins
from honey treated cells were isolated and estimated by Lowry’s method and were
run on sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE).
The binding effect of different components identified in SBH was examined on
estrogen receptor (ER) α and β using Schrodinger Maestro software.
LCMS analysis revealed the presence of 2-hydroxy cinnamic acid, methyl
syringate and fumaric acid in SBH, whereas these compounds were absent in IBH.
The UV-VIS spectrum profile showed highest peak at 284nm, recognized as
hydroxymethylfurfural (HMF) and its amount was seen more in SBH. The total
phenol and flavonoid content was also seen more in SBH than IBH.
Studies on antioxidant assays showed effective scavenging of free radicals by
stingless bee honey. The DPPH, ABTS and SOD free radicals were scavenged by
SBH with IC50 values of36.15, 22 and 79.85 v/v respectively whereas the IBH
scavenged DPPH and ABTS with IC50values of 72.75 and 57.89 v/v respectively.
Stingless bee honeyshowed anti-proliferative activity on cervical cancer cell
line, HeLa and breast cancer cell line, MCF-7 with IC50 value of 66.68 and58.11 v/v
respectively. No toxicity was found on the in vitro safety evaluation done in Vero
and IEC-6 cell lines up to the concentration of 100 v/v. For trypan blue dye
exclusion method, the SBH shown considerable cytotoxic activity towards murine
tumour cells such as DLA (Dalton Lymphoma ascites) and EAC (Ehrlich Ascites
Carcinoma) cell lines in a dose dependant manner with IC50 values of 48.02 and
37.41 v/v respectively.
In protein profiling study, the total amount of intracellular and membrane
bound proteins isolated did not show much variation and in SDS PAGE, the proteins
from cancer cell lines and normal cell lines revealed bands between 97 to 116 KDa.

The docking studies of compounds present in SBH such as 2-hydroxy
cinnamic acid, methyl syringate and fumaric acid with estrogen receptor β shows
more binding, than with estrogen receptor α. The 2-hydroxy cinnamic acid docks
deep well into the binding pockets of estrogen receptor β with docking score of -
6.146 and binding energy -35.607 kcal/mol.
Thus, the characterization of honeys revealed that SBH contain certain
phenolic compounds (2-hydroxy cinnamic acid, methyl syringate and fumaric acid),
whereas these compounds were not identified in IBH. SBH exhibited higher
antioxidant activity against DPPH, ABTS and SOD free radicals and significant
anti-proliferative activity against reproductive cancers such as breast and cervical
cancer cell lines.