No hard evidence yet.
From the National Cancer Institute:
Considerable laboratory evidence from chemical, cell culture, and animal studies indicates that antioxidants may slow or possibly prevent the development of cancer. However, information from recent clinical trials is less clear. In recent years, large-scale, randomized clinical trials reached ...
This is a very interesting question, that has been extensively studied and has received great attention. As such, it has often been vandalized by generic press, leaving people quite confused on the matter.
That antioxidants have physiological effects I would say needs no proof: our body utilises antioxidants such as ascorbate (vitamin C) to keep down the ...
Problem is, like with vitamins and minerals, your body is only going to process a certain amount of something and then dump the rest.
If you have a healthy diet that includes fruits and veggies, you're likely getting all of the anti-oxidants you need.
Skeptoid on high Anti-oxidant claims:
What these tests have found, overall,
is that a certain ...
It makes sense to me that this "guru" knows about the antioxidizing properties of smoke because, as a food chemistry scientist, he is likely to know about this in the context of using smoke for food preservation.
Smoke from burning plant materials, usually wood, has helped to
preserve food ever since our ancestors mastered fire. Smoke’s
The US National Center for Complementary and Alternative Medicine (NCCAM) says that:
Large, long-term studies (randomized, controlled trials) funded
primarily by NIH have generally found that antioxidant supplements
have no beneficial effects.
It is worth noting that NCCAM is a division of the US National Institutes of Health (NIH) which is generally ...
Antioxidant supplements have either no measurable effect or actually increase mortality
Vitamin C and selenium seem harmless but don't reduce mortality; Vitamins A, E and beta-carotene increase mortality
There have been many studies of the effects of antioxidant supplements on health. Some of these studies use fairly dubious techniques and study designs ...
So let's take the research paper from at OP's post at face value. This is the the authors' table summarizing the antioxidants found in tobacco smoke:
Most of the claimed antioxidant effects are due to HCN and isoprene; the paper says
As shown in Table 4, HCN exhibited
the highest antioxidant activity (even more so than
total vapour phase) accounting ...
No, tobacco smoke doesn't act as an antioxidant in the body. Quite the opposite - it causes oxidative stress and introduces free radicals.
Here are a series of references to support this claim. (I have added a few to show it isn't a just single study, like the original question.)
Tobacco Smoke Carcinogens and Lung Cancer
Cigarette smoke contains free ...
Although I'm aware this doesn't answer the question, I think it's worth mentioning that laboratory research in the past 5 years has identified some of the reasons why antioxidants aren't as beneficial as hoped. Some of the clinical trials from NCI's list (from ghoppe's answer) were aborted after a iatrogenic rather than the hoped therapeutic effect of ...