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Enhancement of β-secretase inhibition and antioxidant activities of tempeh, a fermented soybean cake through enrichment of bioactive aglycones

Ahmad A, Ramasamy K, Majeed AB, Mani V

Pharm Biol, 2015 May;53(5):758-66.
PMID: 25756802 DOI: 10.3109/13880209.2014.942791

Soybean and its fermented products are the most common source of isoflavones in human food.

Matched MeSH terms: Amyloid Precursor Protein Secretases/antagonists & inhibitors*
Notch Signalling Pathways and Their Importance in the Treatment of Cancers

Teoh SL, Das S

Curr Drug Targets, 2018;19(2):128-143.
PMID: 28294046 DOI: 10.2174/1389450118666170309143419

BACKGROUND: The Notch pathway is an evolutionarily conserved, intercellular signalling system which is present in all multicellular organisms and mammals. The Notch pathway plays an important role in the embryonic development as it controls cell proliferation, cell differentiation and binary cell fate decisions.
OBJECTIVE: In the present review, we highlight the Notch signalling pathway components i.e. Notch receptors, ligands, effector, and their regulators. We also discuss the tumor biology of the Notch pathway involved in various cancers.
RESULTS: Interestingly, the Notch signalling pathway is dysregulated in many cancers. Notch may serve as oncogene or tumor suppressor and plays an important role in cancers of the liver, pancreas, endometrium of uterus, ovary, prostate, bladder and colon. The activation of Notch pathway plays a vital role in the progression of some cancer. In addition, Notch pathway activation was also shown to drive chemoresistance in cancer, as well. Chemotherapeutically, combined NOTCH1 inhibitor synergistically attenuated chemotherapy-enriched cancer stem cell population both in vitro and in vivo. This may prove to be beneficial in the treatment of cancer.
CONCLUSION: The Notch inhibitors possess anti-proliferative effects on cancer, thereby serving as a new treatment for cancer.

Matched MeSH terms: Amyloid Precursor Protein Secretases/antagonists & inhibitors
Fulltext γ-Secretase Inhibitors and Modulators Induce Distinct Conformational Changes in the Active Sites of γ-Secretase and Signal Peptide Peptidase

Gertsik N, Chau DM, Li YM

ACS Chem. Biol., 2015 Aug 21;10(8):1925-31.
PMID: 26030233 DOI: 10.1021/acschembio.5b00321

γ-Secretase inhibitors (GSIs) and modulators (GSMs) are at the frontline of cancer and Alzheimer's disease research, respectively. While both are therapeutically promising, not much is known about their interactions with proteins other than γ-secretase. Signal peptide peptidase (SPP), like γ-secretase, is a multispan transmembrane aspartyl protease that catalyzes regulated intramembrane proteolysis. We used active site-directed photophore walking probes to study the effects of different GSIs and GSMs on the active sites of γ-secretase and SPP and found that nontransition state GSIs inhibit labeling of γ-secretase by activity-based probes but enhance labeling of SPP. The opposite is true of GSMs, which have little effect on the labeling of γ-secretase but diminish labeling of SPP. These results demonstrate that GSIs and GSMs are altering the structure of not only γ-secretase but also SPP, leading to potential changes in enzyme activity and specificity that may impact the clinical outcomes of these molecules.

Matched MeSH terms: Amyloid Precursor Protein Secretases/antagonists & inhibitors*
Protective effects of total alkaloidal extract from Murraya koenigii leaves on experimentally induced dementia

Mani V, Ramasamy K, Ahmad A, Parle M, Shah SA, Majeed AB

Food Chem Toxicol, 2012 Mar;50(3-4):1036-44.
PMID: 22142688 DOI: 10.1016/j.fct.2011.11.037

Dementia is a syndrome of gradual onset and continuous decline of higher cognitive functioning. It is a common disorder in older persons and has become more prevalent today. The fresh leaves of Murraya koenigii are often added to various dishes in Asian countries due to the delicious taste and flavor that they impart. These leaves have also been proven to have health benefits. In the present study, the effect of total alkaloidal extract from M. koenigii leaves (MKA) on cognitive functions and brain cholinesterase activity in mice were determined. In vitro β-secretase 1 (BACE1) inhibitory activity was also evaluated. The total alkaloidal extract was administered orally in three doses (10, 20 and 30 mg/kg) for 15 days to different groups of young and aged mice. Elevated plus maze and passive avoidance apparatus served as the exteroceptive behavioral models for testing memory. Diazepam-, scopolamine-, and ageing-induced amnesia served as the interoceptive behavioral models. MKA (20 and 30 mg/kg, p.o.) showed significant improvement in memory scores of young and aged mice. Furthermore, the same doses of MKA reversed the amnesia induced by scopolamine (0.4 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.). Interestingly, the brain cholinesterase activity was also reduced significantly by total alkaloidal extract of M. koenigii leaves. The IC50 value of MKA against BACE1 was 1.7 μg/mL. In conclusion, this study indicates MKA to be a useful remedy in the management of Alzheimer's disease and dementia.

Matched MeSH terms: Amyloid Precursor Protein Secretases/antagonists & inhibitors
Fulltext BACE1 inhibitory activity of fungal endophytic extracts from Malaysian medicinal plants

Harun A, James RM, Lim SM, Abdul Majeed AB, Cole AL, Ramasamy K

BMC Complement Altern Med, 2011 Sep 24;11:79.
PMID: 21943123 DOI: 10.1186/1472-6882-11-79

BACKGROUND: BACE1 was found to be the major β-secretase in neurons and its appearance and activity were found to be elevated in the brains of AD patients. Fungal endophytic extracts for BACE1 inhibitory activity and cytotoxicity against PC-12 (a rat pheochromocytoma with neuronal properties) and WRL68 (a non-tumorigenic human hepatic) were investigated.
METHODS: Endophytes were isolated from plants collected from Kuala Pilah, Negeri Sembilan and the National Park, Pahang and the extracts were tested for BACE1 inhibition. For investigation of biological activity, the pure endophytic cultures were cultivated for 14 days on PDA plates at 28°C and underwent semipolar extraction with ethyl acetate.
RESULTS: Of 212 endophytic extracts (1000 μg/ml), 29 exhibited more than 90% inhibition of BACE1 in the preliminary screening. Four extracts from isolates HAB16R13, HAB16R14, HAB16R18 and HAB8R24 identified as Cytospora rhizophorae were the most active with IC(50(BACE1)) values of less than 3.0 μg/ml. The most active extract HAB16R13 was shown to non-competitively inhibit BACE1 with K(i) value of 10.0 μg/ml. HAB16R13 was considered non-potent against PC-12 and WRL68 (IC(50(CT))) of 60.0 and 40.0 μg/ml, respectively).
CONCLUSIONS: This first report on endophytic fungal extract with good BACE1 inhibitory activity demonstrates that more extensive study is required to uncover the potential of endophytes.

Matched MeSH terms: Amyloid Precursor Protein Secretases/antagonists & inhibitors*
Cimigenoside functions as a novel γ-secretase inhibitor and inhibits the proliferation or metastasis of human breast cancer cells by γ-secretase/Notch axis

Jia H, Liu M, Wang X, Jiang Q, Wang S, Santhanam RK, et al.

Pharmacol Res, 2021 Jul;169:105686.
PMID: 34022397 DOI: 10.1016/j.phrs.2021.105686

Breast cancer (BC) occurrence and development tremendously affect female health. Currently breast cancer targeted drugs are still scarce. Natural products have become the main source of targeted drug for breast cancer due to low toxicity and high efficiency. Cimigenoside, natural compound isolated and purified from Cimicifuga dahurica (Turcz.) Maxim has been suggested to utilize for breast cancer treatment, however the mechanism of action has not been elucidated yet. In this article, the antitumor potential of Cimigenoside against breast cancer in vitro and in vivo study. Moreover, we further predicted the possible binding mode of Cimigenoside with γ-secretase through molecular docking studies. The results show that Cimigenoside has a significant inhibitory effect towards the proliferation or metastasis of breast cancer cells via suppressing the Notch signaling pathway-mediated mitochondrial apoptosis and EMT (epithelial mesenchymal transition). In terms of mechanism, Cimigenoside could inhibit the activation of PSEN-1, the catalytic subunit of γ-secretase, and also by cleaving the Notch protein mediated by PSEN-1. Overall, our findings provide scientific support to utilize Cimigenoside as an effective targeted drug for clinical treatment of BC.

Matched MeSH terms: Amyloid Precursor Protein Secretases/antagonists & inhibitors*