I don't see how either of those ideas would prevent corruption.
Imprisoned: There's plenty of corruption in prisons today: Inmates getting drugs, weapons, prostitutes, and other contraband smuggled in, etc. Presumably by definition politicians have political power, so it's hard to see how you would prevent them from using this power to benefit themselves, even in prison.
If the prison is uncomfortable enough, then the only people who would want to be politicians are people who are willing to put up with hardship for the sake of an ideal, or for the thrill of power. I'd think the last thing we want to encourage in politicians is extremism and lust for power.
Isolation: How does that prevent corruption? Someone could still use his power to live in luxury. I suppose if done rigorously enough this would prevent politicians from having friends in the general population, for whom they'd want to twist the law. I worry about politicians making corrupt laws to benefit their friends, but I worry more about them making corrupt laws to benefit people who pay them bribes.
I also worry about politicians having utopian or extremist ideological agendas, that is, ideas of how to build some utopian society that don't work in the real world. I'm certainly not the first to say that politicians today often live in a bubble of wealth and power, isolated from the common people, and so they don't even see it when their utopian schemes don't work in practice. When the problems they cause are pointed out, they dismiss it as minor problems on the way to their grand vision, or reactionaries trying to sabotage their grand vision. Isolating them even more would make this worse.
That said: Many people have struggled for thousands of years to find ways to prevent corruption in politics, and while I suppose some have found a measure of success, clearly no one has solved the problem. I don't suppose that I or anyone else on this board is likely to have the ultimate solution.
But here are some ideas that have been kicked around:
Democracy: Make politicians be elected by the people, as in a republic, rather than inheriting the job from their parents, like kings and nobles, or being selected by the party in power, like in communist countries and other single-party systems. While the system has a lot of flaws, it does mean that politicians whose corruption becomes too extreme and too obvious can be voted out.
Tough anti-corruption laws: Certainly can help. But politicians make the laws, and they are always going to find ways to put in loopholes for themselves and their friends. Indeed, in practice anti-corruption laws often become a source of corruption themselves. For example, here in the U.S. we have campaign finance laws that were passed with the claim that they were going to fight the influence of big money on politics. I was an officer in a Political Action Committee for a while, and I quickly saw that these rules had become a political tool. Competing groups got laws passed that put limits on how much donors who supported their opponents were allowed to contribute while exempting donors who supported themselves. Rules were structured to benefit incumbents at the expense of challengers. I heard one debate in Congress where Senators openly said that the purpose of a proposed new rule was to prevent people from running TV ads criticizing members of Congress. Etc. While in theory anti-corruption laws mean that corrupt politicians are thrown in jail, in practice they often mean that the most corrupt politicians get their political opponents thrown in jail, often on trumped up charges and technicalities.
Term limits: The idea is to limit how much of someone's life he could be a politician, so that no one could spend his whole life as a politician. He would serve for a while, make laws, and then have to go back home and live under those laws. The idea has largely failed because the politicians make the laws, and they've managed to tailor term limits so that while they limit how long one can hold any particular office, the politician can always just move on to another office. When that fails, they become a lobbyist. I think an interesting idea would be to say that no person can hold elected office for more than a total of 10 years (or whatever exact number), all offices combined. So every politician would have to go back to being a private citizen. Sure, some would manage to become lobbyists or political consultants, and so continue to spend their lives in politics. But I think it would be hard for ALL of them to do so. And yes, it would mean that truly honest and able politicians would be forced out. But I think that's a price worth paying.
Part-time government. Have the legislature in session for only a couple of months a year, so the legislators get together, pass laws, and then go home and have to live under the laws they made. Note this is not the same as term limits. A person could still be a politician his whole life. He just can't be a politician every day of the year.
Limited government: No matter how willing a politician is to accept a bribe, for corruption to exist there have to be people willing to pay bribes. (Or engage in other forms of corruptions. Let me just use "bribes" here as shorthand for all forms of corruption.) People are willing to pay bribes when the government has a lot of power to help or hurt them. If the government is passing regulations that will have a huge impact on an industry, big companies in that industry have very good reason to want to have those rules tailored to benefit them: subject their competitors to every possible restriction and inconvenience while they are exempt. If the government is handing out billions of dollars in subsidies, every big-money interest wants to get their hand in the pot. When taxes are high, everyone wants an exemption or deduction for himself. Etc. But if the government is limited, if, say, all it does is enforce basic laws against murder and kidnapping and stealing, and maybe provides some basic infrastructure services like roads and sewers, then there's little reason for anyone to want to pay a bribe. There's nothing to bribe the government official to do, because he has little power to do anything for you or to you.
Personally, I think limited government is the only practical way to truly attack corruption. As long as there are lots of people out there who want to influence government decisions, they'll find a way to do it, legally or illegally.