Bharat - a quick bit of googling does show that modern lenses (from 1990 onwards) do have lubricants inside the lens as well. It also gave me far more knowledge on lubricants than I think I ever want to know. The actual composition of the lubricants vary quite a bit depending on where exactly it needs to be - helicals, damping, AF motor etc etc .... ranging from Lithium based lubricants, to teflon, ceramic etc etc . I did see some warnings on "Silicone grease can react with aluminium alloys to lose its lubricant properties".....
Either way, there is a LOT of very conflicting information out there on what lubricant to use where, however a lot of sources point at lithium based lubricants (which are obviously suspended in an emulsion to vary viscosity). However, I do now know that they do NOT use organic oil-based or water-based lubricants due to separation issues. Whether a grease will separate is not so simple as lithium vs. silicone vs. teflon vs whatever ... there are different grades of lubricants used across different parts of the camera+lens and RH effects that separation as it effects the viscosity of the suspension (the emulsion).
Bottom line: Keep RH and temperature within 'normal' levels.
Aditya, 25% RH is too dry and will start drying out lubricants inside the lens as well.
You might want to experiment a little with the amount of silica gel till you can stabilise at around 40% RH.
I do not have any factual knowledge about this. Looking for some authoritative information.
Do modern lenses have lubricants inside?
If they do, the lubricants will probably be silicone based. Would RH have any effect on silicone based lubricants?