Background:
Amongst the quinolone core structures, 8-hydroxyquinoline (8-HQ or quinolinol)
stands out as the greatest frequently used therapeutic moietiy. This includes the most critical molecules
in medicinal chemistry. Quinolinol remains a broad-spectrum ligand capable of chelating to a
large number of metal ions.
Methods:
The synthesized quinolinols Mannich bases were screened for their in vitro antimicrobial activity
against Staphylococcus aureus (ATTCC 6538), Escherichia coli (ATTCC 7839), Klebsiella
pneumonia (ATCC10131). The antifungal activity of the prepared compounds was assessed against
Candida albicans (10231), Aspergillus niger and Penicillium sp. The antioxidant activity of the
established compounds was assessed by means of α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical
scavenging method.
Results:
The antimicrobial outcomes indicated that all the synthesized compounds excluding 5 and 9b
displayed reasonable antibacterial activity against Staphylococcus aureus (ATTCC 6538) and
Escherichia coli (ATTCC 7839) with an inhibition zones ranging from 13 to 23 mm. However, in the
case of Klebsiella pneumonia (ATCC10131) only compound 6 did not show any activity. The results
also indicated that compounds 2b and 3 were the most potent antibacterial compounds against the
verified strains with minimum inhibitory concentration (MIC) values ranging from 0.05 to 0.5mg/ml. In
the antifungal assay, all compounds showed good activity against Candida albicans (10231) except
compounds 5 and 9b. However, in the case of Aspergillus niger and Penicillium sp. only compounds
2b and 3 showed good activity. In the antifungal assay, MIC values for compounds 2b and 3 ranged
from 0.25 to 2.5 mg/ml against the specified fungal strains. The antioxidant activity was assessed using
the DPPH scavenging activity method. The results indicated that 2b was the most active among all
tested compounds, with almost double the antioxidant activity as compared with that of trolox (positive
control).
Conclusion:
In this work, we describe the synthesis of new Mannich bases comprising 8-HQ (1) and its
derivative (8). The resulted Mannich bases of type 2 were used in transamination reactions with hydrazine
and hydrazine derivatives. The structures of the newly synthesized Mannich bases were confirmed
based on the NMR spectroscopic data and elemental analysis. Antimicrobial and antioxidant activities
were also assessed.
This research was an attempt to find an easy method for beekeeper to predict honey production in the season. Honeybee colonies and empty hives were weighted during the flowering period of anise and Egyptian clover, which considered as main honey crops in Minia region, Egypt Governorate during 2019 and 2020 seasons. Results showed as increase in colony weights during anise flowering period with 12 days interval from 10.500 to 14.014kg in 2019 and from 10.300 to 13.790 kg in 2020. Honey production reached 2.861 kg and 2.944 kg in 2019 and 2020 per colony, respectively. The same results were recorded in the flowering periods of Egyptian clover but the increases of colonies weight were higher in the two seasons. The Egypt clover honey reached 5.199 kg /colony at the end of the flowering seasons of 2019 and 2020 where colony weight increased from 11.375 to 15.048kg in 2019 and from 11.217 to 14.648 kg in 2020 per colony.
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