"retraction" problem persists in some bibtex sources,

[Mike Marchywka]

This seems to be a recurring issue with inconsistent retraction
notice updates. This for example is clearly retracted with big
read notice on page,

https://pubmed.ncbi.nlm.nih.gov/33953832/
Zottero webform did not pick it up AFAICT,

@article{ikram_oral_2021,
	title = {Oral {Administration} of {Gintonin} {Protects} the {Brains} of {Mice} against {Aβ}-{Induced} {Alzheimer} {Disease} {Pathology}: {Antioxidant} and {Anti}-{Inflammatory} {Effects}},
	volume = {2021},
	issn = {1942-0994},
	shorttitle = {Oral {Administration} of {Gintonin} {Protects} the {Brains} of {Mice} against {Aβ}-{Induced} {Alzheimer} {Disease} {Pathology}},
	doi = {10.1155/2021/6635552},
	abstract = {The study was aimed at analyzing the protective effects of gintonin in an amyloid beta- (Aβ-) induced Alzheimer's disease (AD) mouse model. For the development of the Aβ-induced AD mouse model, the amyloid-β (Aβ 1-42) peptide was stereotaxically injected into the brains of mice. Subsequently, gintonin was administered at a dose of 100 mg/kg/day/per oral (p.o) for four weeks daily, and its effects were evaluated by using western blotting, fluorescence analysis of brain sections, biochemical tests, and memory-related behavioral evaluations. To elucidate the effects of gintonin at the mechanistic level, the activation of endogenous antioxidant mechanisms, as well as the activation of astrocytes, microglia, and proinflammatory mediators such as nuclear factor erythroid 2-related factor 2 (NRF-2) and heme oxygenase-1 (HO-1), was evaluated. In addition, microglial cells (BV-2 cells) were used to analyze the effects of gintonin on microglial activation and signaling mechanisms. Collectively, the results suggested that gintonin reduced elevated oxidative stress by improving the expression of NRF-2 and HO-1 and thereby reducing the generation of reactive oxygen species (ROS) and lipid peroxidation (LPO). Moreover, gintonin significantly suppressed activated microglial cells and inflammatory mediators in the brains of Aβ-injected mice. Our findings also indicated improved synaptic and memory functions in the brains of Aβ-injected mice after treatment with gintonin. These results suggest that gintonin may be effective for relieving AD symptoms by regulating oxidative stress and inflammatory processes in a mouse model of AD. Collectively, the findings of this preclinical study highlight and endorse the potential, multitargeted protective effects of gintonin against AD-associated oxidative damage, neuroinflammation, cognitive impairment, and neurodegeneration.},
	language = {eng},
	journal = {Oxidative Medicine and Cellular Longevity},
	author = {Ikram, Muhammad and Jo, Min Gi and Park, Tae Ju and Kim, Min Woo and Khan, Ibrahim and Jo, Myeung Hoon and Kim, Myeong Ok},
	year = {2021},
	pmid = {33953832},
	pmcid = {PMC8068536},
	keywords = {Administration, Oral, Alzheimer Disease, Animals, Anti-Inflammatory Agents, Antioxidants, Disease Models, Animal, Glycoproteins, Male, Mice, Oxidative Stress, Plant Extracts},
	pages = {6635552},
}

The output of "toobib -all",  which picked up  several different
ways to get the bibtex, found again medline was updated ( extracted
with eutils entrez interface to pubmed ) and scraping the webpage
html pickedup the retracted keyword but only using a 
scraping approach for meta data you might not normally do
and which Zoterro apparently ignored. 
Below is the bibtex file it generated with the collection methods
and any mention  of retraction.  

cat xxxx | grep -i "mjmhandler\|etract" | grep -v "final_assembl"
% mjmhandler: toobib guesspubmed
%PT = {Retracted Publication},
pubtype = {Journal Article Retracted Publication},
% mjmhandler: toobib handledoi(crossref)
% mjmhandler: toobib handledoi(crossref)
% mjmhandler: toobib handledoi(crossref)
% mjmhandler: toobib handledoixml ( quality i=0 szr=16 goods=1 )(crossref)
% mjmhandler: toobib handlepdfstrings(crossref)
% mjmhandler: toobib handleadhochtml<-citation
% mjmhandler: toobib handleadhochtml<-og
% mjmhandler: toobib handleadhochtml<-all
keywords = {pmid:33953832, PMC8068536, doi:10.1155/2021/6635552, Retracted Publication, Muhammad Ikram, Min Gi Jo, Myeong Ok Kim, Administration, Oral, Alzheimer Disease / drug therapy*, Alzheimer Disease / prevention \& control*, Animals, Anti-Inflammatory Agents / pharmacology, Anti-Inflammatory Agents / therapeutic use*, Antioxidants / pharmacology, Antioxidants / therapeutic use*, Disease Models, Animal, Glycoproteins / therapeutic use*, Male, Mice, Oxidative Stress / drug effects*, Plant Extracts / pharmacology, Plant Extracts / therapeutic use*, PubMed Abstract, NIH, NLM, NCBI, National Institutes of Health, National Center for Biotechnology Information, National Library of Medicine, MEDLINE},
% mjmhandler: toobib handlegsmeta(scraper)
% mjmhandler: toobib handlegsmeta(html)
% mjmhandler: toobib handleheadless<-handledoi
% mjmhandler: toobib handleheadless<-handlepdfstrings

Toobib may miss a few too but need to keep looking for ways
to get high confidence result :)
I'm not sure what the publisher's webpage would contain but
checking the PMID or PMCID may be helpful as the DOI
info does not seem to be updated. 

-- 

mike marchywka
44 Crosscreek Trail
Jasper GA 30143
USA, Earth marchywka at hotmail.com
 404-788-1216 ORCID: 0000-0001-9237-455X