A number of antioxidant compounds appear to lead to some improvements in memory and then no further decline in Alzheimer's disease.  Here are a few of them:

Treatment of Alzheimer’s Disease with a Cholinesterase Inhibitor Combined with Antioxidants

A formula (formula F) was prepared to counteract oxidative stress (OS) in the brain ((carnosine, coenzyme Q10, vitamin E, vitamin C, Beta-carotene, selenium, L-cysteine and ginkgo biloba)...The MMSE II score remained almost the same in the group treated with donepezil and placebo, whereas some significant improvements were found in the group treated with donepezil plus formula F.

A Case of Alzheimer’s Disease Was Kept Relative Stable with Sequential Therapy for Eight Years

The cognitive outcomes of the patient after receiving eight year’s sequential therapy was significantly better than the expected changes. The use of donepezil [Aricept] in this case also showed similar pinnacle effects around three months followed by a retreat to the baseline. However, with the support from our herbal formula, the beneficial effects sustained for a longer time and her cognition was steadily improved significantly thereafter. Therefore, this phenomena cannot be explained solely by the effects of donepezil, indicating that our herbal formula might work additively and independently to the cholinesterase inhibitor donepezil...A therapeutic approach characterized by programmatic, personalization, as well as dubbed metabolic enhancement for neurodegeneration (MEND protocol) was used. Authors reported that those patients had unprecedented symptom improvement. However, the time of those patients treated with this MEND protocol only ranges from five to 24 months. Our case was treated and observed for much longer time than this study. Meanwhile, a two year polite [pilot] study to check effects of the sequential therapy was conducted in more than two hundred patients recently. Primary results favor the sequential therapy than pure conventional medicine, which will be published soon.

The Chinese herbs used in this formula were similar to the following:

GAPT, also called as GEPT in our previous papers, is a combination of herbal extracts, including eight active components pro rata of Ginsenoside from ginseng 4.4 %, Cistanche 17.3 %, Radix Rehmanniae 17.3 %, Polygala tenuifolia 13 %, Acorus tatarinowii 13 %, Radix Curcumae 13 %, Poria cocos 13 %, Salvia officinalis 9 %.

Improvement of Cognitive Deficit in Alzheimer’s Disease Patients by Long Term Treatment with Korean Red Ginseng

A 24-week randomized open-label study with Korean red ginseng (KRG) showed cognitive benefits in patients with Alzheimer’s disease. To further determine long-term effect of KRG, the subjects were recruited to be followed up to 2 yr. Cognitive function was evaluated every 12 wk using the Alzheimer’s Disease Assessment Scale (ADAS) and the Korean version of the Mini Mental Status Examination (K-MMSE) with the maintaining dose of 4.5 g or 9.0 g KRG per d. At 24 wk, there had been a significant improvement in KRG-treated groups. In the long-term evaluation of the efficacy of KRG after 24 wk, the improved MMSE score remained without significant decline at the 48th and 96th wk. ADAS-cog showed similar findings. Maximum improvement was found around week 24. In conclusion, the effect of KRG on cognitive functions was sustained for 2 yr follow-up, indicating feasible efficacies of long-term follow-up for Alzheimer’s disease.

Maintenance of Cognitive Performance and Mood for Individuals with Alzheimer's Disease Following Consumption of a Nutraceutical Formulation: A One-Year, Open-Label Study.

Nutritional interventions have shown varied efficacy on cognitive performance during Alzheimer's disease (AD). Twenty-four individuals diagnosed with AD received a nutraceutical formulation (NF: folate, alpha-tocopherol, B12, S-adenosyl methioinine, N-acetyl cysteine, acetyl-L-carnitine) under open-label conditions (ClinicalTrials.gov NCT01320527). Primary outcome was cognitive performance. Secondary outcomes were behavioral and psychological symptoms of dementia (BPSD) and activities of daily living. Participants maintained their baseline cognitive performance and BPSD over 12 months. These findings are consistent with improvement in cognitive performance and BPSD in prior placebo-controlled studies with NF, and contrast with the routine decline for participants receiving placebo.

Two more general observations:

We suggest that oxidative stress mediated through NMDAR and their interaction with other molecules might be a driving force for tau hyperphosphorylation and synapse dysfunction. Thus, understanding the oxidative stress mechanism and degenerating synapses is crucial for the development of therapeutic strategies designed to prevent AD pathogenesis.

Oxidative stress has been implicated as a contributing factor to neurodegeneration in Alzheimer's disease. An endogenous, low molecular weight (LMW) inhibitor from Alzheimer's brain inactivates the human brain muscarinic acetylcholine receptor (mAChR). The inhibitor prevents agonist and antagonist binding to the mAChR as assessed by radioligand binding studies...Natural antioxidants and pyrophosphate analogs may improve the effectiveness of acetylcholinesterase inhibitors and prove useful in the treatment and prevention of Alzheimer's disease since the muscarinic acetylcholine receptor is required for memory, and decreased cholinergic function is a critical deficit in Alzheimer's disease.

It certainly appears that certain antioxidants provide a better treatment for Alzheimer's disease than the current standard of care (acetylcholinesterase inhibitors such as Aricept and the NMDA receptor antagonist Namenda)--although perhaps for some the improvement may be even greater when the antioxidants are used in conjunction with current medications (the reverse is almost certainly true).

Hi Lane

Do you know what types and dosage was used or recommend?

Here are the plants and doses used in the Chinese herb study:

Herbal medicine as a traditional therapy is believed to be helpful for dementia in China. The herbal granule was approved by CFDA for clinical use. The GRAPE formula was prescribed for AD patients after every visit according to TCM theory. It consisted mainly of Ren shen (Panax ginseng, 10 g/d), Di huang (Rehmannia glutinosa, 30 g/d), Cang pu (Acorus tatarinowii, 10 g/d), Yuan zhi (Polygala tenuifolia, 10 g/d), Yin yanghuo (Epimedium brevicornu, 10 g/d), Shan zhuyu (Cornus officinalis, 10 g/d), Rou congrong (Cistanche deserticola, 10 g/d), Yu jin (Curcuma aromatica, 10 g/d), Dan shen (Salvia miltiorrhiza, 10 g/d), Dang gui (Angelica sinensis, 10 g/d), Tian ma (Gastrodia elata, 10 g/d), and Huang lian (Coptis chinensis, 10 g/d), supplied by Beijing Tcmages Pharmaceutical Co., LTD. Daily dose was taken twice and dissolved in 150 ml hot water each time.

And the supplements and doses from the nutraceutical study:

Dietary Supplement: Nutriceutical formulation

You might be able to buy panax ginsentg (Korean red ginseng) in capsule form with the grams noted per capsule.  4.5 grams has produced the same improvements as 10 grams but over a longer period of time.  That might be the dose to start with to minimize any potential side effects (such as higher blood pressure).  Here is an example for NOW foods (where my niece works as a chemist; she says they have good quality control, but I am trying not to advertise).  500 mg. would be 5 grams

https://www.nowfoods.com/supplements/panax-ginseng-500-mg-capsules